Showing papers in "Current Zoology in 2014"

Genotoxicity biomarkers in aquatic bioindicators

Abstract: Pollution of the aquatic environment is an ever-growing problem, as waters are the ultimate sink for the large number of xenobiotics from multiple sources. DNA damaging agents have a significant ecological relevance since they are implicated in many pathological processes and exert effects beyond that of individual being active through following generations. A large number of methods have been applied to evaluate genotoxic damage in different aquatic species. Comet assay, as method for de- tecting DNA alterations, and micronucleus test, as an index of chromosomal damage are the most widely applied and validated methods in field studies. These methods were applied in different vertebrate and invertebrate aquatic species, but only mollusk and fish species have been employed in routine biomonitoring programs. Mussels, due to their widely geographical distribution and the suitability for caging represent the bioindicator of choice in field studies. Mytilus species is the most used marine mussel. The use of fish is limited to specific geographic areas. The present review mainly focuses on the application of comet assay and micronucleus test in mussels. A number of biomonitoring studies in mussels, using comet assay or micronucleus test, revealed exposure to different classes of genotoxic compounds with a good discrimination power. The different evidence from the two as- says, reflects different biological mechanisms for the two genetic endpoints, DNA damage and chromosomal damage, suggesting their combined application in the field. Different endogenous and exogenous factors have been shown to modulate the genotoxic responses in mussels, acting as confounding factors in environmental monitoring. The use of standardized protocol for caging, sampling and genotoxity evaluation is critical in biomonitoring studies. The use of a multimarker approach coupling genotoxicity biomarkers with physiological and biochemical factors allows to have a complete picture of the environmental pollution (Current Zoology 60 (2): 273-284, 2014). Keywords Aquatic animals, Genotoxicity, Bioindicator, Biomarker, Micronucleus test, Comet assay, Bivalve, Mussel

Using the movement patterns of reintroduced animals to improve reintroduction success

Abstract: Despite their importance to conservation, reintroductions are still a risky endeavor and tend to fail, highlighting the need for more efficient post-release monitoring techniques. Reintroduced animals are released into unfamiliar novel environments and must explore their surroundings to gain knowledge in order to survive. According to theory, knowledge gain should be followed by subsequent changes to the animal’s movement behavior, making movement behavior an excellent indicator of reintroduction progress. We aim to conceptually describe a logical process that will enable the inclusion of behavior (in particular, movement behavior) in management decision-making post-reintroductions, and to do so, we provide four basic components that a manager should look for in the behaviors of released animals. The suggested components are release-site fidelity, recurring locations, proximity to other individuals, and individual variation in movement behavior. These components are by no means the only possible ones available to a manager, but they provide an efficient tool to understanding animals’ decision-making based on ecological theory; namely, the exploration-exploitation trade-off that released animals go through, and which underlies their behavior. We demonstrate our conceptual approach using data from two ungulate species reintroduced in Israel: the Persian fallow deer Dama mesopotamica and the Arabian oryx Oryx leucoryx [ Current Zoology 60 (4): 515–526, 2014].

Species diversification and phylogeographical patterns of birds in response to the uplift of the Qinghai-Tibet Plateau and Quaternary glaciations

Abstract: The Qinghai-Tibet Plateau (QTP) is well known for being of great importance in the evolution of montane species due to its unique geological history and landform configuration, climate complexity, and diversified habitats. The effect of envi- ronmental changes since the Quaternary on species diversification, population genetic structure, and demography under environ- mental change can be studied using phylogenetic and phylogeographical approaches. Birds are the most well-studied group of all terrestrial vertebrates with regard to their response to climatic changes over time. Herein, we briefly review the species diversifi- cation of birds in response to the uplift of the QTP, focusing on summarizing the different phylogeographical patterns of birds on the Plateau, its southeastern margin, and the Eastern Himalayas and the reasons underlying these patterns. Speciation was found to be closely related to the uplift of the QTP, with different patterns of intraspecific processes: (1) no divergence within a single refuge was identified in a restricted semi-continuous area of the eastern margin of the Plateau; (2) two divergent lineages with separated refugia were located at the south-eastern and north-eastern margins of the plateau; and (3) multiple divergent lineages within subregions were found in the Eastern Himalayas. Glacial movements and induced climate change are considered to be key factors in shaping these different patterns. The species distributed mainly in the heavily ice-covered platform regions of the Pla- teau experienced population expansion following the retreat of the extensive glaciations, whereas the species distributed on the ice-free edges of the plateau maintained their population size at a stable level. Demographic stresses on the edge species might have been mitigated by the milder climate in comparison to their platform-distributed counterparts. Various behavioral and eco- logical characteristics, including dispersal capacity, habitat preference, and elevation specificity, along with evolutionary history might have helped to shape these different phylogeographical patterns (Current Zoology 60 (2): 149-161, 2014).

Individual repeatability in timing and spatial flexibility of migration routes of trans-Saharan migratory raptors

Abstract: P. Lopez-Lopez is supported by a “Juan de la Cierva” postdoctoral grant of the Spanish Ministry of Economy and Competitiveness (reference JCI-2011-09588).

Animal personality and the ecological impacts of freshwater non-native species

Abstract: While the ecological impacts of invasive species have been demonstrated for many taxonomic groups, the potential effects of behavioural variation among non-native individuals (i.e. personality) on these impacts have been largely overlooked. This is despite the fact that recent studies have demonstrated that, by nature, the three first stages of biological invasions (i.e. transport, establishment and spread) can lead to personality-biased populations. Freshwater ecosystems provide a unique oppor- tunity to investigate this issue, notably because the ecological impacts of non-native species have been extensively documented and because animal personality has been widely studied using freshwater model species. Here, we aim at developing some per- spectives on the potential effects of animal personality on the ecological impacts of freshwater non-native species across levels of biological organizations. At the individual level, personality types have been demonstrated to affect the physiolo- gy, metabolism, life history traits and fitness of individuals. We used these effects to discuss how they could subsequently impact invaded popula- tions and, in turn, recipient communities. We also discussed how these might translate into changes in the structure of food webs and the functioning of invaded ecosystems. Finally we discussed how these perspectives could interact with the management of invasive species (Current Zoology 60 (3): 417-427, 2014). Keywords Biological invasions, Behavioural syndromes, Aquatic ecosystems, Temperaments, Behavioural types, Cascading effects

The role of aggression in range expansion and biological invasions

Abstract: Traits that aid in the invasion process should exhibit a gradient across the expansion range in response to changing selection pressures. Aggression has been repeatedly associated with invasion success in many taxa, as it may help invaders to wrestle the resources from other species which enhances their success in a novel environment. However, aggression primarily al- lows individuals to overcome conspecific rivals, providing advantages in competition over resources. Agonistic prowess could therefore increase fitness at both ends of the expansion gradient. Here we review the role of aggression in range expansion of in- vasive species, and its potential role as a driver of range expansion. We analyze how these different mechanisms could affect trait variation in expanding and invasive populations. Specifically, we look at how aggression could help dilate the edges of a popula- tion through niche competition, as well as lead to exclusion from the center (i.e. areas of high population density) by the conspe- cifics. Both of these processes will result in a characteristic spatial distribution of phenotypes related to aggression that could provide insights into the ecological pressures and dynamics of expanding populations, potentially providing clues to their success as niche competitors and invasive species (Current Zoology 60 (3): 401-409, 2014).

Changes in Philornis infestation behavior threaten Darwin's finch survival

Abstract: The conservation behavior framework is useful to identify key linkages between behavior and conservation practice. We apply this framework to a novel host-parasite system on the Galapagos Islands and ask if there have been changes in parasite oviposition behavior and host mortality patterns across the first decade (2004-2013) of its known association. The Dipteran para- site Philornis downsi was first discovered in Darwin's finch nests in 1997 and is the biggest threat to the survival of Galapagos land birds. Host mortality has increased over the past decade. In Dipterans, pupation and pupae size are determined by access to host resources. Here, we test the hypothesis that P. downsi flies are laying eggs in finch nests earlier in the nestling phase to maximize larval feeding time and therefore chance of pupation success before host death. The results show fewer 1 st instar larvae later in the host nesting cycle in support of earlier egg laying behavior by female flies. Between 2004 and 2013, parasite intensity increased from ~28 to ~48 parasites per nest, host mortality increased from ~50% to ~90%, and host age at death decreased from ~11 to ~5 days. The earlier age at host death was correlated with fewer pupae (from ~50% to ~20%) and smaller pupae size (~10% decrease). Changes in parasite behavior reveal new fitness costs to both the parasite and Darwin's finches. These findings un- derscore the need for urgent conservation action to save Darwin's finches from extinction due to a novel, lethal and introduced parasite (Current Zoology 60 (4): 542-550, 2014).

Phenology of high-arctic butterflies and their floral resources: Species-specific responses to climate change

Abstract: Current global warming is particularly pronounced in the Arctic and arthropods are expected to respond rapidly to these changes. Long-term studies of individual arthropod species from the Arctic are, however, virtually absent. We examined butterfly specimens collected from yellow pitfall traps over 14 years (1996-2009) at Zackenberg in high-arctic, north-east Greenland. Specimens were previously sorted to the family level. We identified them to the species level and examined long-term species-specific phenological responses to recent summer warming. Two species were rare in the samples (Polaris fritillary Bolo- ria polaris and Arctic blue Plebejus glandon) and statistical analyses of phenological responses were therefore restricted to the two most abundant species (Arctic fritillary, B. chariclea and Northern clouded yellow Colias hecla). Our analyses demonstrated a trend towards earlier flight seasons in B. chariclea, but not in C. hecla. The timing of onset, peak and end of the flight season in B. chariclea were closely related to snowmelt, July temperature and their interaction, whereas onset, peak and end of the flight season in C. hecla were only related to timing of snowmelt. The duration of the butterfly flight season was significantly positively related to the temporal overlap with floral resources in both butterfly species. We further demonstrate that yellow pitfall traps are a useful alternative to transect walks for butterfly recording in tundra habitats. More phenological studies of Arctic arthropods should be carried out at the species level and ideally be analysed in context with interacting species to assess how ongoing cli- mate change will affect Arctic biodiversity in the near future (Current Zoology 60 (2): 243-251, 2014).

Individual consistency and sex differences in migration strategies of Scopoli's shearwaters Calonectris diomedea despite year differences

Abstract: Recently-developed capabilities for tracking the movements of individual birds over the course of a year or longer has provided increasing evidence for consistent individual differences in migration schedules and destinations. This raises questions about the relative importance of individual consistency versus flexibility in the evolution of migration strategies, and has implica- tions for the ability of populations to respond to climatic change. Using geolocators, we tracked the migrations of Scopoli's shearwaters Calonectris diomedea breeding in Linosa (Italy) across three years, and analysed timing and spatial aspects of their movements. Birds showed remarkable variation in their main wintering destination along the western coast of Africa. We found significant individual consistency in the total distance traveled, time spent in transit, and time that individuals spent in the win- tering areas. We found extensive sex differences in scheduling, duration, distances and destinations of migratory journeys. We also found sex differences in the degree of individual consistency in aspects of migration behaviour. Despite strong evidence for individual consistency, which indicates that migration journeys from the same bird tended to be more similar than those of dif- ferent birds, there remained substantial intra-individual variation between years. Indeed, we also found clear annual differences in departure dates, return dates, wintering period, the total distance traveled and return routes from wintering grounds back to the colony. These findings show that this population flexibly shifts migration schedules as well as routes between years in response to direct or indirect effects of heterogeneity in the environment, while maintaining consistent individual migration strategies (Cur- rent Zoology 60 (5): 631-641, 2014).

Predicting wild boar damages to croplands in a mosaic of agricultural and natural areas

Abstract: Crop damages by wildlife is a frequent form of human-wildlife conflict. Identifying areas where the risk of crop dama- ges is highest is pivotal to set up preventive measures and reduce conflict. Species distribution models are routinely used to pre- dict species distribution in response of environmental changes. The aim of this paper was assessing whether species distribution models can allow to identify the areas most at risk of crop damages, helping to set up management strategies aimed at the mitiga- tion of human-wildlife conflicts. We obtained data on wild boar Sus scrofa damages to crops in the Alta Murgia National Park, Southern Italy, and related them to landscape features, to identify areas where the risk of wild boar damages is highest. We used MaxEnt to build species distribution models. We identified the spatial scale at which landscape mostly affects the distribution damages, and optimized the regularization parameter of models, through an information-theoretic approach based on AIC. Wild boar damages quickly increased in the period 2007-2011; cereals and legumes were the crops more affected. Large areas of the park have a high risk of wild boar damages. The risk of damages was related to low cover of urban areas or olive grows, interme- diate values of forest cover, and high values of shrubland cover within a 2-km radius. Temporally independent validation data demonstrated that models can successfully predict damages in the future. Species distribution models can accurately identify the areas most at risk of wildlife damages, as models calibrated on data collected during only a subset of years correctly predicted damages in the subsequent year (Current Zoology 60 (2): 170-179, 2014).

Do animal eyespots really mimic eyes

Abstract: The diversity of anti-predator adaptations in the natural world has long been an active area of research in evolutionary and behavioural biology. A common visually-obvious feature found on prey are 'eyespots', being approximately circular mark- ings often with concentric rings and conspicuous colours. These are found on a range of animals, especially adult and larval Lepidoptera and fish. One of the most widespread functions of eyespots seems to be to intimidate or startle predators: delaying, preventing or halting an attack. However, while the fact that they can influence predators in this way is uncontroversial, the mechanism(s) behind why they are effective is debated. Traditionally, they have been assumed to work by mimicking the eyes of the predator's own enemies, and much research in this field is conducted under the implicit or explicit assumption that this theory is correct. However, eyespots might work simply by being highly salient stimuli that promote sensory overload, biases, or neo- phobic reactions in predators. A range of recent studies has aimed to test these alternatives. Here, we critically evaluate this work and what it tells us about the mechanisms underlying eyespot function. We conclude that although eye mimicry is plausible, there remains a lack of evidence to support it and most observations are at least equally consistent with alternative mechanisms. Finally, we also discuss how the debate can be resolved (Current Zoology 60 (1): 2636, 2014).

Chemical deception among ant social parasites

Abstract: Deception is widespread throughout the animal kingdom and various deceptive strategies are exemplified by social parasites. These are species of ants, bees and wasps that have evolved to invade, survive and reproduce within a host colony of another social species. This is achieved principally by chemical deception that tricks the host workers into treating the invading parasite as their own kin. Achieving levels of acceptance into typically hostile host colonies requires an amazing level of deception as social insects have evolved complex species- and colony-specific recognition systems. This allows the detection of foreigners, both hetero- and con-specific. Therefore, social parasitic ants not only have to overcome the unique species recognition profiles that each ant species produces, but also the subtle variations in theses profiles which generate the colony-specific profiles. We present data on the level of chemical similarity between social parasites and their hosts in four different systems and then discuss these data in the wider context with previous studies, especially in respect to using multivariate statistical methods when looking for differences in these systems.

Ecogenotoxicology in earthworms: A review

Abstract: Pollutant dynamics and bioavailability greatly differ in soil and aquatic systems. Therefore, specific approaches and models are needed to assess the impact of soil contamination to terrestrial ecosystems. Earthworms among other soil inverte- brates have received more attention because of their ecological importance. They represent a dominant part of the soil biomass and are soil engineers regulating important soil processes, notably fertilization. The release in soils of pollutants known for their persistence and/or their toxicity is a concern. Exposure of terrestrial species to pollutants that may alter genomic function has be- come an increasing topic of research in the last decade. Indeed, genome disturbances due to genetic and epigenetic mechanisms may impair growth, as well as reproduction and population dynamics in the long term. Despite their importance in gene expres- sion, epigenetic mechanisms are not yet understood in soil invertebrates. Until now, pollutant-induced changes in genome ex- pression in natural biota are still being studied through structural alteration of DNA. The first biomarker relating to genotoxicant exposure in earthworms from multi-contaminated soils reported is DNA adducts measurements. It has been replaced by DNA breakage measured by the Comet assay, now more commonly used. Functional genomic changes are now being explored owing to molecular "omic" technologies. Approaches, objectives and results are overviewed herein. The focus is on studies dealing with genotoxicity and populational effects established from environmentally-relevant experiments and in situ studies (Current Zoology 60 (2): 255-272, 2014).

An integrative view of the signaling phenotype: Dynamic links between signals, physiology, behavior and social context

Abstract: Signal traits are often linked with the physiological state and behavior of their bearer. Direct examination of the caus- al links among these variables has provided substantial insight into the information content of signals, and into the costs and bene- fits of signal expression. Yet recent empirical work suggests that the social context in which signals are developed and displayed can play a major role not only in how signals are received, but also in coordinating and mediating the signaling phenotype itself. Here we review both well-established and emerging evidence for direct feedbacks among an individual's physiological state, be- havior, and signal elaboration. We then describe an integrative view of signaling that takes into account the bidirectional rela- tionships among components of phenotype and the social context in which signals are developed and displayed. Integrating dy- namic feedback between context and phenotype within models of the evolution and maintenance of signals may yield insights into how signals evolve, how signaling phenotypes are coordinated and maintained on ecological and evolutionary time scales, and how static signals continue to convey relevant phenotypic information about their bearer through time (Current Zoology 60 (6): 739-754, 2014 ).

Compensatory foraging in Trinidadian guppies: Effects of acute and chronic predation threats

Abstract: In response to acute predation threats, prey may sacrifice foraging opportunities in favour of increased predator avoidance. Under conditions of high or frequent predation risk, such trade-offs may lead to reduced fitness. Here, we test the pre- diction that prey reduce the costs associated with lost opportunities following acute predation threats by exhibiting short-term compensatory foraging responses. Under semi-natural conditions, we exposed female guppies Poecilia reticulate from high and low predation risk sites to one of three levels of acute predation threat (high, intermediate or low concentrations of conspecific alarm cues). Our results confirm previous reports, demonstrating that guppies from a high predation site were consistently 'bolder' (shorter escape latencies) and exhibited graded threat-sensitive responses to different simulated threat levels while those from the low predation site were 'shyer' and exhibited non-graded responses. Most importantly, we found that when guppies from low predation sites resumed foraging, they did so at rates significantly lower than baseline rates. However, guppies from high preda- tion sites resumed foraging either at rates equal to baseline (in response to low or intermediate risk stimuli) or significantly in- creased relative to baseline rates (in response to high risk stimuli). Together, these results highlight a complex compensatory be- havioral mechanism that may allow prey to reduce the long-term costs associated with predator avoidance (Current Zoology 60 (3): 323-332, 2014 ).

Antipredator deception in terrestrial vertebrates

Abstract: Deceptive antipredator defense mechanisms fall into three categories: depriving predators of knowledge of prey's presence, providing cues that deceive predators about prey handling, and dishonest signaling. Deceptive defenses in terrestrial vertebrates include aspects of crypsis such as background matching and countershading, visual and acoustic Batesian mimicry, active defenses that make animals seem more difficult to handle such as increase in apparent size and threats, feigning injury and death, distractive behaviours, and aspects of flight. After reviewing these defenses, I attempt a preliminary evaluation of which aspects of antipredator deception are most widespread in amphibians, reptiles, mammals and birds (Current Zoology 60 (1): 16 25, 2014).

Bite me: Blue tails as a‘risky-decoy’defense tactic for lizards

Abstract: Many lizard species use caudal autotomy to escape entrapment. Conspicuous coloration may increase the likelihood of being attacked, but if that attack can be directed towards the autotomous tail this may ultimately increase the chances of the lizard surviving a predatory attack. We tested the hypothesis that brightly-colored function to divert predatory attention away from the head and body using pairs of blue-tailed and all-brown clay model lizards. Predatory bird attacks on the 24 blue-tailed models occurred sooner (P = 0.001) than attacks on the 24 all-brown models, and over 7 days, blue-tailed models were attacked more often than all-brown models (P = 0.007). Blue-tailed models were, however, more frequently attacked on the tail than other parts of the body (P < 0.001), while all-brown models were more frequently attacked on the head and body (P = 0.019) which would be more likely to be fatal for a real lizard. Our results suggest that models with a blue tail were more conspicuous than all-brown models, attracting attacks sooner and more often, but that the attacks were predominantly directed at the tail. It is better for individuals to be attacked unsuccessfully many times, than successfully just once. Having a brightly colored tail may, therefore, act as a ‘risky decoy’. Despite increased conspicuousness, a blue tail increases the likelihood that the lizard would be able to effect escape through caudal autotomy rather than being grabbed by the head or body

From deception to frankness: Benefits of ontogenetic shift in the anti-predator strategy of alder moth Acronicta alni larvae

Abstract: Animals can avoid predation by masquerading as objects that are not food to their predators. Alder moth Acronicta alni larvae go through an impressive ontogenetic change from masquerade to highly conspicuous appearance: early larval stages resemble bird droppings but in the last instar the larval coloration changes into striking yellow-and-black stripes. We hypothe- sized that such a change may be driven by differential predation favoring dissimilar anti-predator strategies in different life stages. We show with a series of laboratory assays that larvae are distasteful to birds regardless of their developmental stage, suggesting that ontogenetic color change is not driven by the differential chemical defense. Birds showed higher variance in hesitation to- ward conspicuous prey; some individuals hesitated long time before attacking whereas all birds attacked instantly masqueraded prey. We also found that the activity level of the larvae increased with age, which fits to the fact that larvae need to move from foliage to pupation sites. In the field by using artificial larvae resembling the two life-history stages we found predation risk to vary during the season: In early summer larger yellow-and-black larvae were attacked most, whereas later in the summer small 'bird-dropping-larvae' suffered the highest predation. We conclude that the ontogenetic switch from masquerading to aposema- tism is adaptive most likely because actively moving prey cannot mimic immotile objects and thus, aposematism during the ac- tive and vulnerable period when larvae are searching for pupation sites becomes beneficial (Current Zoology 60 (1): 114122,

Foraging site recursion by forest elephants Elephas maximus borneensis

Abstract: Recursion by herbivores is the repeated use of the same site or plants. Recursion by wild animals is rarely investigated but may be ubiquitous. Optimal foraging theory predicts site recursion as a function of the quality of the site, extent of its last use, and time since its last use because these influence site resource status and recovery. We used GPS collars, behaviour and site sampling to investigate recursion to foraging sites for two elephant Elephas maximus borneensis herds in the Lower Kinabatangan Wildlife Sanctuary, Borneo, over a 12 month period. Recursion occurred to 48 out of 87 foraging sites and was most common within 48 hours or between 151–250 days, indicating two different types of recursion. Recursion was more likely to occur if the site had previously been occupied for longer. Moreover, the time spent at a site at recursion was the same as the time spent at the site on the first occasion. The number of days that had passed between the first visit and recursion was also positively correlated with how much time was spent at the site at recursion. Habitat type also influenced the intensity of site-use, with more time spent at recursion within riverine/open grass areas along forest margins compared to other habitat types. Recursion is a common behaviour used by the elephants and its pattern suggests it may be a foraging strategy for revisiting areas of greater value. The qualities of recursion sites might usefully be incorporated into landscape management strategies for elephant conservation in the area

A trait-based approach to assess climate change sensitivity of freshwater invertebrates across Swedish ecoregions

Abstract: Freshwater habitats and organisms are among the most threatened on Earth, and freshwater ecosystems have been subject to large biodiversity losses. We developed a Climate Change Sensitivity (CCS) indicator based on trait information for a selection of stream- and lake-dwelling Ephemeroptera, Plecoptera and Trichoptera taxa. We calculated the CCS scores based on ten species traits identified as sensitive to global climate change. We then assessed climate change sensitivity between the six main ecoregions of Sweden as well as the three Swedish regions based on Illies. This was done using biological data from 1,382 stream and lake sites where we compared large-scale (ecoregional) patterns in climate change sensitivity with potential future exposure of these ecosystems to increased temperatures using ensemble-modelled future changes in air temperature. Current (1961~1990) measured temperature and ensemble-modelled future (2100) temperature showed an increase from the northernmost towards the southern ecoregions, whereas the predicted temperature change increased from south to north. The CCS indicator scores were highest in the two northernmost boreal ecoregions where we also can expect the largest global climate change-induced increase in temperature, indicating an unfortunate congruence of exposure and sensitivity to climate change. These results are of vital importance when planning and implementing management and conservation strategies in freshwater ecosystems, e.g., to mitigate increased temperatures using riparian buffer strips. We conclude that traits information on taxa spe- cialization, e.g., in terms of feeding specialism or taxa having a preference for high altitudes as well as sensitivity to changes in temperature are important when assessing the risk from future global climate change to freshwater ecosystems (Current Zoology 60 (2): 221-232, 2014).

Neurochemistry as a bridge between morphology and behavior: Perspectives on aggression in insects

Abstract: Aggression is a common behavioral trait shared in many animals, including both vertebrates and invertebrates. How- ever, the type and intensity of agonistic encounters and displays can vary widely both across and within species, resulting in complicated or subjective interpretations that create difficulties in developing theoretical models that can be widely applied. The need to easily and objectively identify quantifiable behaviors and their associated morphologies becomes especially important when attempting to decipher the neurological mechanisms underlying this complex behavior. Monoamines, neuropeptides, and pheromones have been implicated as important neuromodulators for agonistic displays in both invertebrates and vertebrates. Ad- ditionally, recent breakthroughs in insect research have revealed exciting proximate mechanisms important in aggression that may be broadly relevant, due to the relatively high conservation of these neurochemical systems across animal taxa. In this review, we present the latest research demonstrating the importance of monoamines, neuropeptides, and pheromones as neuromodulators for aggression across a variety of insect species. Additionally, we describe the stalk-eyed fly as a model system for studying aggres- sion, which integrates physiological, morphological, and neurochemical approaches in exploring detailed mechanisms responsi- ble for this common yet complex behavior. We conclude with our perspective on the most promising lines of future research aimed at understanding the proximate and ultimate mechanisms underlying aggressive behaviors (Current Zoology 60 (6): 778- 790, 2014 ).

Evolutionary consequences of deception: Complexity and informational content of colony signature are favored by social parasitism

Abstract: Nestmate recognition codes show remarkable chemical complexity, involving multiple biochemical pathways. This complexity provides the opportunity to evaluate the ecological and social conditions that favor the evolution of complex signaling. We investigated how the chemical signatures of three populations of the social paper wasp Polistes biglumis differed in terms of concentration of hydrocarbons, proportions of branched hydrocarbons and overall variation. We tested whether the variation in chemical signatures among populations could be explained by the prevalence of social parasites or whether this was just an effect of local abiotic conditions which influenced the composition of the hydrocarbon cuticular layer. We studied the chemical signa- ture in three populations in which obligate social parasites differed in the selection pressures they imposed on host populations. Within each population, we restricted our analyses to non-parasitized hosts, to avoid potential short-term effects of parasite pres- ence on the host chemical signatures. We found that host colonies in parasitized populations had more diverse profiles than the parasite-free population. Moreover, the overall concentration of hydrocarbons and the relative proportion of branched hydrocar- bons were larger in the parasitized populations, relative to the non-parasitized one. This is to our knowledge the first evidence in favour of the hypothesis that different traits in the host chemical signatures as a whole undergo evolutionary changes resulting from directional or balancing selection imposed by social parasites. We conclude that obligate social parasites act as 'engines of diversity' on host chemical signatures and operate in favor of a geographic mosaic of diverging communication codes (Current Zoology 60 (1): 137148, 2014). Keywords Polistes, Brood parasitism, Cipher, Nestmate recognition, Hydrocarbons, Geographic mosaic, Crozier's paradox

Predatory pollinator deception: Does the orchid mantis resemble a model species?

Abstract: Cases of imperfect or non-model mimicry are common in plants and animals and challenge intuitive assumptions about the nature of directional selection on mimics. Many non-rewarding flower species do not mimic a particular species, but at- tract pollinators through 'generalised food deception'. Some predatory animals also attract pollinators by resembling flowers, perhaps the most well known, yet least well understood, is the orchid mantis Hymenopus coronatus. This praying mantis has been hypothesised to mimic a flower corolla and we have previously shown that it attracts and captures pollinating insects as prey. Predatory pollinator deception is relatively unstudied and whether this occurs through model mimicry or generalised food decep- tion in the orchid mantis is unknown. To test whether the orchid mantis mimics a specific model flower species we investigated similarities between its morphology and that of flowers in its natural habitat in peninsular Malaysia. Geometric morphometrics were used to compare the shape of mantis femoral lobes to flower petals. Physiological vision models were used to compare the colour of mantises and flowers from the perspective of bees, flies and birds. We did not find strong evidence for a specific model flower species for the orchid mantis. The mantis' colour and shape varied within the range of that exhibited by many flower pet- als rather than resembling one type in particular. We suggest that the orchid mantis resembles an average, or generalised flower-like stimulus. Thus predatory pollinator deception in the orchid mantis is likely to function as a form of generalised food deception, as opposed to model mimicry (Current Zoology 60 (1): 90103, 2014). Keywords Mimicry, Orchid mantis, Hymenopus coronatus, Generalised food deception, Aggressive mimicry

More than mimicry? Evaluating scope for flicker-fusion as a defensive strategy in coral snake mimics

Abstract: Coral snakes and their mimics often have brightly colored banded patterns, generally associated with warning colora- tion or mimicry. However, such color patterns have also been hypothesized to aid snakes in escaping predators through a "flicker-fusion" effect. According to this hypothesis, banded color patterns confuse potential predators when a snake transitions from resting to moving because its bands blur together to form a different color. To produce this motion blur, a moving snake's bands must transition faster than the critical flicker-fusion rate at which a predator's photoreceptors can refresh. It is unknown if coral snakes or their mimics meet this requirement. We tested this hypothesis by measuring the movement speed and color pat- terns of two coral snake mimics, Lampropeltis triangulum campbelli and L. elapsoides, and comparing the frequency of color transitions to the photoreceptor activity of the avian eye. We found that snakes often produced a motion blur, but moving snakes created a blurring effect more often in darker conditions, such as sunrise, sunset, and nighttime when these snakes are often active. Thus, at least two species of coral snake mimics are capable of achieving flicker-fusion, indicating that their color patterns may confer an additional defense aside from mimicry (Current Zoology 60 (1): 123130, 2014).

The role of behavior in tern conservation

Abstract: Behavioral research has long had an important role in the conservation of terns (Aves: Sternidae). Habitat management and restoration of breeding colony sites depends on knowledge of the cues used to select colony and nest sites. For example, conspecific attraction with playback and decoys is commonly used to bring terns to suitable colony sites and habitat modification is often used to increase the availability of suitable nest sites. Tern colonies are interconnected by dispersal, and a metapopulation approach is needed for effective management. Population dynamics are therefore affected by behaviors that influence the frequency of movement among colony sites: site fidelity, natal and breeding dispersal, and group adherence. The monogamous breeding system of terns should keep effective population size similar to census population size, but variation in sex ratios (likely resulting from sex differences in behavior) and in parental quality can result in a smaller than expected effective population size. In addition to the behavior of terns, knowledge of the behavior of predators on terns contributes to management plans, because predator be- havior can sometimes be manipulated and predation is often performed by only a few specialized individuals. Other examples of links between tern behavior and conservation are also briefly reviewed, such as behavioral toxicology research and studies of be- havioral responses to human disturbance and manmade structures. More work is needed on the behavior of migratory terns at staging sites, stopover sites and wintering grounds, and on the behavior of less well-studied species and species in less well-studied geographic regions (Current Zoology 60 (4): 500-514, 2014).

Metabolic enzymes in seasonally acclimatized and cold acclimated rufous-collared sparrow inhabiting a Chilean Mediterranean environment

Abstract: Due to the higher energy requirements of birds during winter, it is predicted that the activities of metabolic enzymes (e.g., citrate synthase, CS and cytochrome C oxidase, COX) should increase in tandem with increases in rates of energy expendi- ture (e.g., basal metabolic rate, BMR). However, there is mixed support for the hypothesis of enzymatic acclimatization. Fur- thermore, there is little information about the effect of ambient temperature on energetics and tissue enzyme activity levels in passerines inhabiting seasonal Mediterranean environments. In this study we evaluated the interplay between BMR and enzyme activities of freshly caught individuals of the passerine Zonotrichia capensis in winter and summer in a Mediterranean environ- ment from central Chile, and also in warm (30°C) and cold (15°C) lab-acclimated birds. The results revealed a lack of seasonal variation in BMR, thermal conductance and in the activity of CS and COX. However, we found higher BMR and lower thermal conductance in cold-acclimated than in warm-acclimated birds. Also, total CS activity was higher in the flight muscles of cold-acclimated than in warm-acclimated birds. We found also a significant correlation between BMR and total CS activity in pectoral muscle. Although some authors have suggested that BMR mainly depends on the metabolic intensity and mass of internal organs, our results revealed that skeletal muscles such as the flight muscles may also affect BMR. Finally, differences in the accli- mation and acclimatization responses in Rufous-collared sparrows suggest that large-scale oscillations in the physical environment might maintain the capacity for flexibility in thermogenic traits through generations (Current Zoology 60 (3): 338-350, 2014).

What is the sound of fear? Behavioral responses of white-crowned sparrows Zonotrichia leucophrys to synthesized nonlinear acoustic phenomena

Abstract: Fear and anxiety may be adaptive responses to life-threatening situations, and animals may communicate fear to oth- ers vocally. A fundamental understanding of fear inducing sounds is important for both wildlife conservation and management because it helps us understand how to design repellents and also how (and why) animals may be negatively impacted by anthro- pogenic sounds. Nonlinear phenomena—sounds produced by the desynchronization of vibrations in a sound production sys- tem—are commonly found in stress-induced animal vocalizations, such as in alarm calls, mobbing calls, and fear screams. There are several functional hypotheses for these nonlinear phenomena. One specific hypothesis is the unpredictability hypothesis, which suggests that because nonlinear phenomena are more variable and somewhat unpredictable, animals are less likely to ha- bituate to them. Animals should, therefore, have a prolonged response to sounds with nonlinear phenomena than sounds without them. Most of the studies involving nonlinear phenomena have used mammalian subjects and conspecific stimuli. Our study fo- cused on white-crowned sparrows (Zonotrichia leucophrys ssp. oriantha) and used synthesized acoustic stimuli to investigate behavioral responses to stimuli with and without nonlinear phenomena. We predicted that birds would be less relaxed after hear- ing a stimulus with a nonlinear component. We calculated the difference from baseline of proportion of time spent in relaxed be- haviors and performed pair-wise comparisons between a pure tone control stimulus and each of three experimental stimuli, in- cluding a frequency jump up, a frequency jump down, and white noise. These comparisons showed that in the 30-60 s after the playback experiment, birds were significantly less relaxed after hearing noise or an abrupt frequency jump down an octave but not an abrupt frequency jump up an octave or a pure tone. Nonlinear phenomena, therefore, may be generally arousing to animals and may explain why these acoustic properties are commonly found in animal signals associated with fear (Current Zoology 60 (4): 534-541, 2014).

Effects of environmental variability and offspring growth on the movement ecology of breeding Scopoli’s shearwater Calonectris diomedea

Abstract: Most seabird species display colonial behavior during the breeding period which implies that food resources around breeding sites can easily go depleted. Seabirds need to both reach profitable areas, which can be located far from the colony, and return to the colony regularly. In this context, flexibility in movement behavior may be crucial for breeding success. During chick-rearing, Procellariformes species can alternate short trips lasting 1–4 days for chick provisioning with longer trips for self-provisioning in what has been called a dual-foraging strategy. We analyzed foraging trips from 136 Scopoli’s shearwaters from three Mediterranean colonies tracked with GPS during 6 chick-rearing seasons to assess whether the adoption of a dual foraging strategy depends on the quality of habitat surrounding the colony. We found a marked dual-foraging strategy only in birds from the Linosa colony which was the largest colony in terms of breeding pairs and was characterized by having a lower marine habitat quality. Birds from this colony performed foraging trips that extended up to 369 km from the nest and lasted more than 10 days. In general, the decision to perform long lasting trips was triggered by lower values of primary production and higher offspring weight. Contrary to expectation, the decision to feed far from the colony was not related to the parents’ weight. At the same time, despite the higher productivity offered by distant areas, the higher proportion of long trips performed by birds breeding in poor areas was not sufficient to maintain the same body mass as the ones breeding in richer areas.

Does defensive posture increase mimetic fidelity of caterpillars with eyespots to their putative snake models

Abstract: Organisms often evolve behaviours that increase or reinforce the protection from predators afforded by their morphological defences. For example, mimetic animals may adopt postures or locomotory behaviours that emulate a characteristic feature of their model to increase predator deception. Caterpillars with eyespots are thought to mimic snakes, and when threatened many of these caterpillars adopt a posture that appears to enhance this resemblance. Herein we evaluate the quantitative strength of evidence of behavioural mimicry in the caterpillars of 14 species by comparing how closely a series of putative snake-mimicking caterpillars resemble snakes while at rest and when threatened. Specifically, we quantified the head morphology and eye position of a range of snake species, as well as the shape of the apparent head (i.e. anterior body segments) and position of eyespots in caterpillars resting or in their defensive posture. This allowed us to objectively examine evidence for an increased resemblance to either snakes generally, or to Viperidae snakes specifically, upon adopting the defensive posture. Widening the anterior body segments during the defensive posture typically made caterpillars appear more viper-like as opposed to more snake-like in general. Enhanced resemblance to vipers upon mounting the defensive posture was apparent only from the dorsal view. Laterally, caterpillars more closely resembled snakes in the resting posture and shifting to the defensive posture instead reduced mimetic fidelity. Overall we found evidence for behavioural mimicry in all 14 species examined. We highlight that objectively quantifying mimetic fidelity can help identify key features involved in deception.

Age and ovarian development are related to worker personality and task allocation in the ant Leptothorax acervorum

Abstract: In social insects, workers of different morphological castes and age are known to act differently. Yet, it is unclear how body size and ovarian development influence worker personalities (i.e. consistent behavioral variation) and task allocation in similar aged ant workers of monomorphic species. Behavioral variation is thought to be a key element of division of labor, but few studies have linked worker personality to task allocation. We investigated individual behavior in Leptothorax acervorum ant workers at two time points during the first three months of their life and in two different settings. We observed worker behavior in the nest (i.e. task allocation) and in standardized aggression, exploration and brood care experiments (i.e. personality) and found behavioral repeatability in foraging and exploration. Further, workers acted consistently across settings: workers with a more aggressive and exploratory personality type were more active in the nest. Moreover, ovarian development was associated with worker personality and task allocation: older workers with well-developed ovaries foraged less, but were more aggressive and exploratory. In accordance with the typical age-polyethism of social insects, workers became more active and foraged more as they grew older. Consequently, our study suggests that task allocation in Leptothorax acervorum is not only influenced by ovarian development and age, but moreover by the personalities of its workers.