Behavioral niche partitioning in a sympatric tiger beetle assemblage and implications for the endangered Salt Creek tiger beetle
TL;DR: Results of this study strongly indicate that competition among these species for resources has been reduced by the adaptation of different thermoregulatory behaviors such as spending time in shallow water, avoiding the sun during the hottest parts of the day, and by positioning their body against or away from the soil.
Abstract: How behavioral patterns are related to niche partitioning is an important question in understanding how closely related species within ecological communities function. Behavioral niche partitioning associated with thermoregulation is well documented in tiger beetles as a group. Co-occurring species of salt flat tiger beetles have adapted many thermoregulatory behaviors to cope with this harsh ecosystem. On first examination these beetles appear to occur in overlapping microhabitats and therefore compete for resources. To determine if behavioral niche partitioning is allowing multiple species to occur within the same harsh salt flat ecosystem we observed Cicindela nevadica lincolniana, Cicindela circumpicta, Cicindela fulgida, and Cicindela togata between 8:00 h and 21:00 h and recorded all behaviors related to thermoregulation using a digital voice recorder. Results of this study strongly indicate that competition among these species for resources has been reduced by the adaptation of different thermoregulatory behaviors such as spending time in shallow water, avoiding the sun during the hottest parts of the day, and by positioning their body against or away from the soil. The endangered C. n. lincolniana appears to rely most heavily on the shallow water of seeps for their diurnal foraging behavior (potentially limiting their foraging habitat), but with the advantage of allowing foraging during the hottest times of the day when potential competitors are less frequent. Ironically, this association also may help explain C. n. lincolniana's susceptibility to extinction: beyond the loss of saline wetlands generally, limited seeps and pools even within remaining saline habitat may represent a further habitat limitation within an already limited habitat.
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TL;DR: The consequences of the cholesteric geometry in living matter are described, which are far from being fully defined and understood, and discusses various perspectives.
Abstract: Liquid crystals play an important role in biology because the combination of order and mobility is a basic requirement for self-organisation and structure formation in living systems. Cholesteric liquid crystals are omnipresent in living matter under both in vivo and in vitro conditions and address the major types of molecules essential to life. In the animal and plant kingdoms, the cholesteric structure is a recurring design, suggesting a convergent evolution to an optimised left-handed helix. Herein, we review the recent advances in the cholesteric organisation of DNA, chromatin, chitin, cellulose, collagen, viruses, silk and cholesterol ester deposition in atherosclerosis. Cholesteric structures can be found in bacteriophages, archaea, eukaryotes, bacterial nucleoids, chromosomes of unicellular algae, sperm nuclei of many vertebrates, cuticles of crustaceans and insects, bone, tendon, cornea, fish scales and scutes, cuttlebone and squid pens, plant cell walls, virus suspensions, silk produced by spiders and silkworms, and arterial wall lesions. This article specifically aims at describing the consequences of the cholesteric geometry in living matter, which are far from being fully defined and understood, and discusses various perspectives. The roles and functions of biological cholesteric liquid crystals include maximisation of packing efficiency, morphogenesis, mechanical stability, optical information, radiation protection and evolution pressure.
218 citations
TL;DR: It is demonstrated that the carapace has concave cells whereas the artificial films have convex cells, contrary to expectation in the literature and may provide inspiration for fabricating spatial wavelength-specific light modulators and optical packet switching in routing technologies.
47 citations
TL;DR: Detailed depth time series retrieved from 89 electronic data storage tags attached to 4 species of skate were analysed to determine preferred depth ranges, and 2 species were found to segregate spatially into 2 groups, with one group having a significantly shallower core annual depth range than the other.
Abstract: A sympatric assemblage of morphologically similar predators is expected to exhibit fine-scale habitat segregation, or resource partitioning, to reduce the effects of direct competition. This principle has been well studied for predators in terrestrial ecosystems. In the marine environment, the fine-scale spatial segregation of sympatric species of large predators is poorly understood because detailed movement and behavioural data are often not available across multiple species within the same timeframe. The ways in which co-occurring congeneric predators separate spatially is even less well understood. Medium-sized species of skates (genus Raja) co-occur in temperate habitats of the north-east Atlantic Ocean, share similar morphologies and have distributional ranges that overlap significantly in the western English Channel ecosystem. In the present study, detailed depth time series retrieved from 89 electronic data storage tags attached to 4 species of skate were analysed to determine preferred depth ranges. The 4 species were found to segregate spatially into 2 groups, with one group having a significantly shallower core annual depth range than the other. To our knowledge, fine-scale segregation by depth has not been observed previously. Interestingly, the members of each species group appeared complementary, each group comprising species with different dietary preferences and with a larger and smaller body size. An understanding of how core depth ranges differ and how these species utilise vertical habitat could potentially enable geographic ranges around the coast to be predicted, with important implications for how these species interact with fisheries and Marine Protected Areas.
25 citations
TL;DR: The results clearly show high habitat specialization of most studied taxa, as well as importance of water reservoirs in species distribution in the Sahara Desert, and that most studied Cicindelidae were characterised by unique habitat preferences and did not co-occur with other ones.
Abstract: Tiger beetles are a group of predatory insects occurring mainly in diverse sandy areas, with particular species often characterised by narrow habitat preferences, which makes them both very important bioindicators for determining patterns of biodiversity and a flagship group for nature conservation. However, the precise roles of particular habitat parameters in the distribution of these beetles in desert areas are almost unknown. Habitat preferences for four tiger beetles species were analysed in Tunisia. Fifty samples from a major part of the country were collected, for which climate data, macrohabitat types. and soil parameters (soil humidity, salinity, pH, and structure) were studied. Here we show that most studied Cicindelidae were characterised by unique habitat preferences and did not co-occur with other ones, including two taxa found as habitat specialists, occurring in only one type of macrohabitat. Two other species were noted as more eurythopic and occupied 2–3 macrohabitat types, with Lophyra flexuosa as the most ubiquitous species not related to the measured parameters. The presence of a source of water (understood as a part of the habitat type, such as river banks and oases, or high soil humidity) was found as the most important factor in the distribution of the studied tiger beetle species. The present study is the first one focused on habitat preferences and habitat specialization of Cicindelidae fauna of Maghreb, and one of only a few in Africa.
5 citations
TL;DR: Field observation revealed that niche utilization would be relevant for differentiating these closely related species, and two new species are proposed, Cylindera ooasp.
Abstract: Tiger beetles have been recognized primarily based on morphological characters. However, the variations of elytral maculation and coloration sometimes lead to misjudgment in species classification and the overlooking of the existence of cryptic species. Recently, specimens of two endemic species of Taiwanese Cylindera, C. sauteri and C. pseudocylindriformis, exhibit morphologically recognizable forms, indicating that some undescribed species may exist. To clarify their taxonomic status, morphological characteristics including male genitalia were examined and two mitochondrial genes, COI and 16S rDNA, and one nuclear 28S rDNA were analyzed. Molecular phylogenetic inferences indicated that both forms in both species are reciprocally monophyletic. Moreover, molecular dating showed the forms diverged approximately 1.3 million years ago. Two new species, Cylindera ooa sp. nov. and Cylindera autumnalis sp. nov., are thereby described. The main recognizable characteristics separating C. ooa sp. nov. from C. sauteri are the lack of a triangular spot at the middle edge of elytron and the elongated but not rounded subapical spot. For C. autumnalis sp. nov., the apical lunula near the elytral suture is thickened but not linear and slender, and its elytra are more metallic brownish than those of C. pseudocylindriformis. Although their aedeagi characteristics are not distinctive, the body size of the proposed two new species is different. Field observation revealed that niche utilization would be relevant for differentiating these closely related species.
3 citations
Cites background from "Behavioral niche partitioning in a ..."
...In addition, physiological differences (Schultz and Hadley 1987), oviposition behaviors (Hoback et al. 2000, 2001), and thermoregulatory behaviors (Brosius and Higley 2013) are also relevant to niche differentiation of tiger beetles....
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...2000, 2001), and thermoregulatory behaviors (Brosius and Higley 2013) are also relevant to niche differentiation of tiger beetles....
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References
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Book•
12 Jul 1994
TL;DR: Introduction.
Abstract: Introduction. Body Water. Cuticular Transpiration. Respiratory Transpiration. Excretion and Osmoregulation. The Uptake of Water. Water Relations of Eggs. Balancing Salts and Water. Thermoregulation and Relations.
550 citations
"Behavioral niche partitioning in a ..." refers background in this paper
...Many tiger beetles are found in environments where temperatures are capable of exceeding 60◦C, a lethal temperature for most insect species (Hadley, 1994)....
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TL;DR: An analysis of ecological characteristics of 23 threatened and 72 nonthreatened butterfly species reveals that threatened butterflies are characterized by narrow niche breadth, restricted resource distribution, poor dispersal ability, and short flight period, and an ecological extinction risk rank is constructed.
Abstract: Understanding the ultimate causes of population declines and extinction is vital in our quest to stop the currently rampant biodiversity loss. Comparison of ecological characteristics between threatened and nonthreatened species may reveal these ultimate causes. Here, we report an analysis of ecological characteristics of 23 threatened and 72 nonthreatened butterfly species. Our analysis reveals that threatened butterflies are characterized by narrow niche breadth, restricted resource distribution, poor dispersal ability, and short flight period. Based on the characteristics, we constructed an ecological extinction risk rank and predicted which of the currently nonthreatened species are at the highest risk of extinction. Our analysis reveals that two species currently classified as nonthreatened are, in fact, at high risk of extinction, and that the status of a further five species should be reconsidered.
282 citations
"Behavioral niche partitioning in a ..." refers background in this paper
...lincolniana, are thought to be more susceptible to extinction due to habitat destruction (Kammer, Baumiller & Ausich, 1997; Kotiaho et al., 2005)....
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...Organisms that are highly specialized, such as C. n. lincolniana, are thought to be more susceptible to extinction due to habitat destruction (Kammer, Baumiller & Ausich, 1997; Kotiaho et al., 2005)....
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Book•
04 Oct 2001
TL;DR: Tiger beetles are one of the most obvious and ubiquitous families of any insect taxon and some 2300 species are found on nearly all the land surfaces of the earth as discussed by the authors.
Abstract: Tiger beetles are one of the most obvious and ubiquitous families of any insect taxon-some 2300 species are found on nearly all the land surfaces of the earth. Their frequently showy colors, brazen behavior, and ability to live in habitats ranging from dry, alkaline lakebeds to tropical rain forests have captured the interest of amateur and professional entomologists alike. Although tiger beetles have been widely studied, the wealth of knowledge has been synthesized only briefly in a few sources.In Tiger Beetles, David L. Pearson and Alfried P. Vogler provide for the first time a detailed integration and summary of all that is known about the family Cicindelidae. The book's early chapters cover anatomy, distribution, and natural history. Pearson and Vogler build from these basics to show the usefulness of tiger beetles for exploring questions in genetics, biogeography, ecology, behavior, and conservation. As bioindicators, the tiger beetles present in an area may allow biologists to pinpoint places with the richest diversity of animal and plant life. The use of tiger beetles as model organisms has made possible or greatly enhanced many areas of research, including molecular phylogeny, the function of acute hearing, spatial modeling, and physiology of vision.
140 citations
TL;DR: Mandible length was found to be correlated with median prey size captured by tiger beetle species in Sulphur Springs Valley, Arizona, USA, and preliminary comparisons of sympatric tiger beetles from Canada and East Africa showed divergence but with a lower ratio.
Abstract: Mandible length was found to be correlated with median prey size captured by tiger beetle species in Sulphur Springs Valley, Arizona, USA. Base resource measurements of live arthro- pod prey showed a relatively narrow size range (1-10.4 mm) on pond edges and a broad size range (1-30.4 mm) in upland grassland habitat within the valley. Ten of 11 tiger beetle species sympatric on the pond edge habitat showed considerable convergence in mandible length, likely in response to the narrow prey size available. The 6 grassland species, however, fit into 3 distinct size classes, 2 species in each size class. On a given grassland site, normally no more than 1 species from each size class was present. The ratio of mandible lengths for sympatric species in the grassland habitat was consistently ? 1.35, which corresponds to Hutchinsonian ratios. Preliminary comparisons of sympatric tiger beetles from Canada and East Africa showed divergence but with a lower ratio (1.24-1.27).
100 citations
TL;DR: Field observations established that the feeding levels of wild larvae and adults in several habitats over five years was lower than the level which produced maximum offspring and survival in the laboratory, except on permanent pond edges where food was abundant.
Abstract: Using an assemblage of tiger beetles in SE Arizona, USA, as test organisms, the potential for food as a limiting resource in each of the life cycle stages was determined. Laboratory experiments established at what levels food quantity affected adults and larvae. Adult females at low feeding levels produced significantly fewer eggs and larvae than females at high feeding levels. Larvae at low feeding levels took significantly longer to pass through all three larval stages, and their pupae and emergent adults were significantly smaller than those individuals raised at higher feeding levels. Large adults survived longer than small adults when deprived of food. Small adult females produced fewer eggs and larvae at low feeding levels than larger conspecific females at the same feeding levels. Field observations established that the feeding levels of wild larvae and adults in several habitats over five years was lower than the level which produced maximum offspring and survival in the laboratory, except on permanent pond edges where food was abundant. Year to year fluctuations in food availability indicated that food in some habitats was more likely limiting in some years than others.
97 citations