The evolution of polyandry : multiple mating and female fitness in insects

It is clear that the above can lead to confusion when scientists of different countries are trying to communicate with each other. Another example is the burrowing rodent called a gopher found throughout the western United States. In the southeastern United States the term gopher refers to a burrowing turtle very similar to the desert tortoise found in the American southwest. One final example; two North American mammals known as the elk and the caribou are known in Europe as the reindeer and the elk. We never sing “Rudolph the Red-nosed elk”! Confused? This was the reason for creating an internationally recognized system of naming organisms. To avoid confusion, living organisms are assigned a scientific name based on Latin or Latinized words. The English sparrow is Passer domesticus or Passer domesticus (italics or underlining these two names is the official written representation of a scientific name). Using a uniform naming system allows scientists from all over the world to recognize exactly which life form a scientist is referring to. The naming process is called the binomial system of nomenclature. Passer is comparable to a surname and is called the genus, while domesticus is the specific or species name (like your given name) of the English sparrow. Now scientists can give all sparrow-like birds the genus Passer but the species name will vary. All similar genera (plural for genus) can be grouped into another, “higher” category (see below). Study the following for a more through understanding of taxonomy. Taxonomy Analogy Kingdom: Animalia Country

Diversity of life

The aim of this review is to consider variation in mating preferences among females. We define mating preferences as the sensory and behavioural properties that influence the propensity of individuals to mate with certain phenotypes. Two properties of mating preferences can be distinguished: (1) "preference functions'-the order with which an individual ranks prospective mates and (2) "choosiness'-the effort an individual is prepared to invest in mate assessment. Patterns of mate choices can be altered by changing the costs of choosiness without altering the preference function. We discuss why it is important to study variation in female mating behaviour and identify five main areas of interest: Variation in mating preferences and costs of choosiness could (1) influence the rate and direction of evolution by sexual selection, (2) provide information about the evolutionary history of female preferences, (3) help explain inter-specific differences in the evolution of secondary sexual characteristics, (4) provide information about the level of benefits gained from mate choice, (5) provide information about the underlying mechanisms of mate choice. Variation in mate choice could be due to variability in preference functions, degree of choosiness, or both, and may arise due to genetic differences, developmental trajectories or proximate environmental factors. We review the evidence for genetic variation from genetic studies of heritability and also from data on the repeatability of mate-choice decisions (which can provide information about the upper limits to heritability). There can be problems in interpreting patterns of mate choice in terms of variation in mating preferences and we illustrate two main points. First, some factors can lead to mate choice patterns that mimic heritable variation in preferences and secondly other factors may obscure heritable preferences. These factors are divided into three overlapping classes, environmental, social and the effect of the female phenotype. The environmental factors discussed include predation risk and the costs of sampling; the social factors discussed include the effect of male-male interactions as well as female competition. We review the literature which presents data on how females sample males and discuss the number of cues females use. We conclude that sexual-selection studies have paid far less attention to variation among females than to variation among males, and that there is still much to learn about how females choose males and why different females make different choices. We suggest a number of possible lines for future research.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/DB79D853FB764ADB3C114417B7012081/S0006323196005014a.pdf/div-class-title-variation-in-mate-choice-and-mating-preferences-a-review-of-causes-and-consequences-div.pdf

Variation in mate choice and mating preferences: a review of causes and consequences.

According to much evolutionary thinking, males of promiscuous species are able to produce quantities of sperm that are virtually unlimited and should be selected to mate indiscriminately with all available females. However, sperm are generally delivered in batches (ejaculates or spermatophores) that may include many millions of gametes. Males are limited with respect to the number of ejaculates they can deliver and the time required to restore depleted reserves. Because ejaculates are a limited resource, prudence would be expected in the allocation of ejaculates to females. Among the forces acting to limit the number of females with which a promiscuous male mates are high pregnancy initiation requirements, sperm competition, female choice and control, and the costs and risks of searching. Optimal strategies for ejaculate allocation will vary with the operational sex ratio. Males can and do discriminate among females as potential mating partners. The problems of limited ejaculatory capacity and male choice...

https://www.jstor.org/stable/pdfplus/2461181.pdf

Ejaculate Cost and Male Choice

B (order Chiroptera) are ecologically more diverse than any other group of mammals. Numerous morphological, physiological, and behavioral adaptations of sensory and motor systems permit bats access to a wide range of habitats and resources at night. The more than 750 species of the suborder Microchiroptera occupy most terrestrial habitats and climatic zones and exploit a great variety of foods, ranging from insects and other arthropods, small vertebrates, and blood to fruit, leaves, nectar, flowers, and pollen. Echolocation is one of the adaptations that make bats so successful. Echolocating animals emit signals of high frequency (mostly ultrasonic) and analyze the returning echoes to detect, characterize, and localize the reflected objects. Sophisticated echolocation systems have evolved only in the bat suborder Microchiroptera and in dolphins. Less efficient systems have been reported for a few species of the bat suborder Megachiroptera and for some birds (Henson and Schnitzler 1980). Bats use echolocation for orientation in space, that is, for determining their position relative to the echo-producing environment. In addition, many bats, especially those that hunt for flying insects, use echolocation to detect, identify, and localize prey. Bats use a wide variety of species-specific signal types differing in frequency structure, duration, and sound pressure level (SPL). In addition, signal structure varies depending on the echolocation task confronting the bat. Search signals that are emitted when bats search for prey differ from approach signals that are emitted when they approach prey. The echolocation signals and hearing systems of bats are well adapted for gathering behaviorally relevant information (e.g., Schnitzler and Henson 1980, Neuweiler 1989, Fenton 1990, Denzinger et al. forthcoming). In this article we describe the echolocation behavior of insect-eating bats and show how differing circumstances such as habitat type, foraging mode, and diet favor different signal types. To demonstrate relationships between echolocation and ecological conditions, we outline the perceptual tasks that must be performed by foraging bats and discuss the suitability of typical elements of echolocation signals for solving such problems. We then define habitat types according to the problems they impose on bats and relate the observed variability in signal structure to ecological constraints set by habitat type and foraging mode. Perceptual problems for foraging bats Foraging bats confront a multitude of problems when flying to their hunting grounds and searching for prey. These problems differ depending on where bats hunt, what they eat, and how they acquire their food. For example, bats hunting for insects in the open encounter conditions different from those that search for prey near the edges of vegetation, in vegetation gaps, in dense forest, or near the ground. The problems also differ depending upon whether they capture moving prey in flight (aerial mode) or mostly stationary prey from surfaces such as leaves or ground (gleaning mode) or water (trawling mode). Foraging bats must detect, classify, and localize an insect and discriminate between echoes of prey and echoes of unwanted targets such as twigs, foliage, or the ground, referred to as clutter echoes, or simply “clutter.”For many bats echolocation delivers all of the information they need to catch an insect.

https://www.jstor.org/stable/10.1641/0006-3568%282001%29051%5B0557%3AEBIEB%5D2.0.CO%3B2

Echolocation by insect-eating bats

Insectivorous bats have influenced the development of antipredator behavior in moths, green lacewings, crickets, and mantids; until recently, such adaptations were unknown in katydids. Foliage-gleaning bats in Panama can use the female-attracting, airborne calling songs of nocturnal katydids to locate prey. They also feed heavily on these insects. Katydid species sympatric with these bats exhibit markedly reduced calling song duty cycles. Males supplement shortened songs with complex, species-specific tremulations that generate vibrations that are inaudible to bats but reach conspecific females through a shared plant substrate. Female katydids do not call audibly but are also preyed on in large numbers, perhaps as a result of moving toward calling males.

http://science.sciencemag.org/content/sci/238/4823/64.full.pdf

Bat Predation and Its Influence on Calling Behavior in Neotropical Katydids

Orthopteran Mating Systems: Sexual Competition In A Diverse Group Of Insects

Myopophyllum speciosum is a pseudophylline katydid (Tettigoniidae) from the neotropics that generates unusually high ultrasonic frequencies as the dominant carrier in its calling song. Male calls average only 148 ms duration and are given at long intervals: 8.7 s. Pairing is completed with vibrational signals, generated at closer range by body oscillation (tremulation). Two distinctive vibrational motor patterns, short and long, are produced by both sexes. Physical parameters of the sound and vibratory signals of this species are described. The relatively high-Q carrier frequency (mean = 81 kHz) varies between males over a range of 20 kHz but does not predict a singer's body size. Short tremulations are much more intense than long as measured by acceleration. Descriptions of the songs of three other pseudophylline species with unusually high principal carriers (65–105 kHz) are also presented.



Eavesdropping by predatory bats offers the most plausible selective explanation for the features of M. speciosum's signal system. This hypothesis is supported by the species' sexually dimorphic defensive spination: males, the sound-signalling sex, have metafemoral spines of greater size and distinctive orientation. Evidence for eavesdropping and for alternative hypotheses is assessed. Other neotropical tettigoniids in rainforest understorey also employ elaborate vibratory signals (species of Choeroparnops, Schedocentrus, Docidocercus, Copiphora) and some show a trend to reduce or even to eliminate their use of airborne sound. Some rainforest tettigoniids may have replaced acoustic with vibrational signalling as a response to bat eavesdropping.

High ultrasonic and tremulation signals in neotropical katydids (Orthoptera: Tettigoniidae)

Calling display and mating behaviour of Copiphora rhinoceros Pictet (Orthoptera: Tettigoniidae)

Sexually receptive females of Conocephalus nigropleurum were tested in an arena at 30 °C for responsiveness to tape-recorded models of male calling song. Exit bearing from the arena relative to speakers was the response criterion. Models were the song of a male recorded at 30 °C, the same recording with tegminal opening sounds deleted, and the same male's song at 25 °C. A fourth model was a recording of two males, 10 cm apart, singing at 30 °C, less than 10 cm equidistant from the microphone. Female choice was established for all model pairings. Preferences could not be ranked on a single scale, indicating that discriminatory criteria change with particular combinations. The model with two males proved most effective.In presenting a choice between 'two males' and 'single male with intact song (30 °C),' when the broadcast amplitude levels of these models were identical for both speakers, four times as many phonotactic exits occurred in the quadrant of the speaker broadcasting dual song than occurred in the...

Glenn K. Morris

Papers

Bat Predation and Its Influence on Calling Behavior in Neotropical Katydids

Orthopteran Mating Systems: Sexual Competition In A Diverse Group Of Insects

High ultrasonic and tremulation signals in neotropical katydids (Orthoptera: Tettigoniidae)

Calling display and mating behaviour of Copiphora rhinoceros Pictet (Orthoptera: Tettigoniidae)

Phonotactic preferences of female meadow katydids (Orthoptera: Tettigoniidae: Conocephalus nigropleurum)