Papers by Marie Herberstein
Australian crab spiders Thomisus spectabilis sit on the petals of flowers and ambush prey such as... more Australian crab spiders Thomisus spectabilis sit on the petals of flowers and ambush prey such as honeybees. White-coloured T. spectabilis reflect in the UV (UV+ spiders) and previous research has shown that their presence, curiously, attracts honeybees to daisies. We applied an UV-absorber (Parsol®) to create UV-absorbing (UV–) spiders that did not reflect any light below 395·nm wavelength. These physical changes of visual signals generated by crab spiders caused honeybees to avoid flowers with UV– spiders on their petals. They also affected the perception of UV– spiders by honeybees and a potential avian predator (blue tits). Compared to UV+
spiders, UV– spiders produced less excitation of the UV- photoreceptors in honeybees and blue tits, which translated into a reduced UV-receptor contrast and a reduced overall colour contrast between UV– spiders and daisy petals. Our results reveal that a clean physical elimination of reflection in the UV range affects perception in predators and prey and ultimately changes the behaviour of prey.
Behavioral Ecology and Sociobiology, 2002
The costs of courtship and mating may include increased risks of predation, the transmission of p... more The costs of courtship and mating may include increased risks of predation, the transmission of pathogens, and a loss of foraging opportunities. Thus, a female's decision to tolerate a courting male will depend upon how these costs offset the benefits of mating, which will depend on her reproductive and nutritional status. While these costs may be similar for mated and unmated females, the benefits of mating will be less for mated than virgin females. However, the cost of lost foraging opportunities may be higher for females with fewer nutritional reserves necessary for forming eggs. We examined how these costs and benefits influence the courtship and mating behaviour of male and female orb-web spiders, Argiope keyserlingi. In the field, females on webs that also contained a courting male intercepted fewer prey items per hour than females on webs without a male. In the laboratory, the presence of a courting male at the hub also attracted mantid predators to the web, increasing the risk of predation for both male and female. Staged mating experiments in the laboratory revealed that the frequency of female attacks and pre-copulatory cannibalism was greater among mated than virgin females. Feeding history did not affect aggression in virgin females but, among mated females, food-deprived spiders attacked and cannibalized males more frequently than sated females and only the latter ever remated. These differences in female behaviour influenced male mating strategies. Choice experiments demonstrated that males preferred to venture onto the silk threads of virgin rather than those of mated females. Similar patterns of mate selectivity were observed in the field; females with narrow abdomens attracted more males to the webs than females with broad abdomens, and copulations were observed more frequently among females with narrow abdomens. These smaller females are likely to be virgins that have recently molted. Males that preferentially mate with virgin females will not only avoid potentially fatal attacks but also obtain, on average, a higher fertilization success.
Austral Ecol, 2008
Environmental conditions such as light level, background contrast and temperature might influence... more Environmental conditions such as light level, background contrast and temperature might influence a spider's prey capture success and risk of predation. Thus it may often be advantageous for spiders to adjust webbuilding behaviour in response to variation in these environmental conditions. This hypothesis was examined in a study of the construction of webs and web decorations (conspicuous strands of silk at the hub of the web) of the orb-web spider Argiope keyserlingi . Web decorations are thought to have one or more separate functions. They may attract prey, deter predators or advertise the web to oncoming birds, thus preventing web damage. In this series of experiments, relationships between weather parameters and the construction of webs and web decorations were considered. In complementary laboratory experiments, A. keyserlingi spiders were exposed to two different light levels (700 and 90 lx), background contrasts (black and white) and temperature conditions (20 and 26 Њ C). Of the available weather parameters, only temperature was significantly related to web decorating behaviour but not to web size. In the laboratory, temperature also influenced web-decorating behaviour, and spiders in dim light (700 lx) constructed larger webs and longer decorations. Background contrast did not significantly alter web size or web decorations. These data suggest that when prey availability is reduced at low temperatures, spiders may use web decorations to attract prey to the web. Similarly, in dim light, spiders may build more and larger decorations to increase the visual signal to approaching prey or to advertise the web to oncoming birds.
Behavioral Ecology and Sociobiology, Mar 8, 2013
A reduced predation risk is considered to be a major adaptive advantage of sociality. While most ... more A reduced predation risk is considered to be a major adaptive advantage of sociality. While most studies are concerned with non-predatory prey species, group-living predators are likely to face similar threats from higher-order predators. We studied the relationship between group size and predation risk in the subsocial crab spider Diaea ergandros by testing predictions from theoretical models including attack abatement as well as the formation of protective retreats. In a field survey, we found predatory clubionid spiders in 35 % of the D. ergandros nests and as predicted, nest size did not correlate with predator presence. In a subsequent laboratory experiment, we observed survival probability, nest construction activity and feeding behaviour including weight development between groups of different sizes as well as in the absence or presence of a predator. Large groups had an advantage in terms of survival and growth compared to smaller groups or single individuals. They also built significantly larger nests than smaller groups, supporting the idea of protective retreat formation being an adaptive benefit to group living. Even though clubionids did attack D. ergandros, they did not significantly affect overall mortality of D. ergandros. The feeding experiment showed that spiders fed on a larger proportion of flies in the presence of a predator. However, these groups gained significantly less weight compared to the control groups, indicating that the potential predators not only act as predators but also as food competitors, constituting a twofold cost for D. ergandros.
Ethol Ecol Evol, 2006
Animals are expected to alter their foraging behaviour depending on the risk of predation. We tes... more Animals are expected to alter their foraging behaviour depending on the risk of predation. We tested this idea using the orb-web spider Argiope keyserlingi. We measured the foraging investment of spiders in terms of web size and size of silk decorations in the presence of a predatory praying mantid, Pseudomantis albofimbriata. However, no limited evidence that A. keyserlingi alters its decorating behaviour and no evidence that this spider alters its web architecture in response to the presence of a mantid predator. We suggest that these ...
In unpalatable prey, long-wavelength colors such as red or yellow are often thought to be aposema... more In unpalatable prey, long-wavelength colors such as red or yellow are often thought to be aposematic (warning) signals, due to their high conspicuousness. However, conspicuousness depends on the visual physiology of the receivers. Tectocoris diophthalmus is a shieldback stinkbug with highly variable coloration; individuals may be all orange or have blue-green iridescent patches of variable size. Prior research has demonstrated the defenses of T. diophthalmus can induce avoidance learning in birds but not praying mantids, and that geographic patterns in variation may relate to the local density of arthropod predators. In this study, we use visual modeling and behavioral assays to test how praying mantids Hierodula majuscula may impose directional selection pressure on the coloration of T. diophthalmus. Mantids have monochromatic vision with peak sensitivity in the "green" region of the spectrum. Using a receptor excitation model, we show that orange bugs are much less conspicuous than iridescent conspecifics and may be inconspicuous against their typical green leaf background. In behavioral assays, mantids detected iridescent bugs from a greater distance on average. In binary choice experiments, mantids showed no color preference at short range, but approached iridescent bugs significantly more often when the choice had to be made at a greater distance, and could not distinguish between orange bugs and unoccupied leaves at distance. Together, this evidence suggests that H. majuscula should impose strong directional selection against iridescent bugs in nature, and that orange coloration may be performing dual roles of crypsis to mantids but aposematic signaling to birds.
Spider Ecophysiology, 2012
Functional Ecology, 2014
1. Cryptic coloration may evolve in response to selective pressure imposed by predators, yet effe... more 1. Cryptic coloration may evolve in response to selective pressure imposed by predators, yet effective intraspecific communication may require some level of detectability. This creates a tension between the benefits of sexually selected visual traits and the predatory costs imposed by greater conspicuousness, and little is known about how this tension may be ameliorated in highly cryptic species. 2. We explore these competing demands in the false garden mantid Pseudomantis albofimbriata, a colour-blind and seemingly cryptic insect. We use reflectance spectrometry and receptor-noise modelling to characterize the conspicuousness of mantid body regions in the visual systems of mates (mantids), as well as potential predators (birds) and prey (bees). We then use condition manipulation and conspecific choice tests to further explore the colour traits of interest. 3. Based on visual modelling, we find that male mantids are inconspicuous to conspecifics, prey and predatorsthat is, they are chromatically and achromatically cryptic. In contrast, female mantids are chromatically cryptic to all potential receivers, but their abdomens are achromatically conspicuous. Our food manipulation experiment shows that females in good condition (and therefore with more eggs) have brighter abdomens than females in poor condition. Choice assays show male mantids are consistently attracted to females bearing brighter abdomens. 4. Our results reveal brightness-mediated sexual signalling in a colour-blind and classically cryptic insect. By communicating in the only visual channel available to them, female mantids are conspicuously signalling their quality to mates, while potentially minimizing their conspicuousness to predators and prey. Furthermore, by signalling with only a single body region, female mantids are apparently using coincident disruptive coloration to further decrease detectability to potential eavesdroppers. 5. Our data reveal a novel example of the way in which the trade-off between sexual selection for conspicuousness and natural selection for crypsis may be mediated in a visual signalling system. Such signals may be common in apparently cryptic species, and this study once again demonstrates the importance of analysing visual signals beyond the capacity of human vision.
PLOS ONE, 2015
In alpine Australia, Orthoptera are abundant, dominant herbivores, important prey species, and ho... more In alpine Australia, Orthoptera are abundant, dominant herbivores, important prey species, and hosts for parasites and parasitoids. Despite the central role of orthopterans in alpine ecosystems, the impact of parasites on orthopteran populations is under-explored. In this study we describe the relationship between parasite prevalence and host sex, body size and year of collection. We accessed an existing, preserved collection of 640 Kosciuscola tristis collected from across its range between 2007 and 2011. Upon dissection we collected juvenile parasites and used molecular tools to identify them to three families (Nematoda; Mermithidae, and Arthropoda: Diptera: Tachinidae and Sarcophagidae). The prevalence of nematodes ranged from 3.5% to 25.0% and dipterans from 2.4% to 20.0%. Contrary to predictions, we found no associations between parasite prevalence and grasshopper sex or size. Although there was an association between prevalence of both nematodes and dipterans with year of collection, this is likely driven by a small sample size in the first year. Our results provide a foundation for future studies into parasite prevalence within the alpine environment and the abiotic factors that might influence these associations.
Journal of insect physiology, 2015
The sterile male technique is a common method to assign paternity, widely adopted due to its rela... more The sterile male technique is a common method to assign paternity, widely adopted due to its relative simplicity and low cost. Male sterility is induced by exposure to sub lethal doses of chemosterilants or irradiation, the dosage of which has to be calibrated for every species to provide successful male sterilisation, without affecting male physiology and behaviour. While the physiological effects of sterilisation are usually assessed for each study, the behavioural ones are rarely analysed in detail. Using the orb web spider Argiope keyserlingi as a model we first tested (1) the validity of the thread assay, which simulates male courtship behaviour in a standardised context, as a proxy representing courtship on a female web. We then investigated (2) the effectiveness of male sterilisation via irradiation and (3) its consequences on male courtship behaviour. Our results validate the thread assay and the sterile male technique as legitimate tools for the study of male courtship beha...
Scientific reports, 2013
During courtship, individuals transfer information about identity, mating status and quality. How... more During courtship, individuals transfer information about identity, mating status and quality. However, male web-building spiders face a significant problem: how to begin courting female spiders without being mistaken for prey? Male Argiope spiders generate distinctive courtship vibrations (shudders) when entering a female's web. We tested whether courtship shudders delay female predatory behaviour, even when live prey is present in the web. We presented a live cricket to females during playbacks of shudder vibrations, or white noise, and compared female responses to a control in which we presented a live cricket with no playback vibrations. Females were much slower to respond to crickets during playback of shudder vibrations. Shudder vibrations also delayed female predatory behaviour in a related spider species, showing that these vibrations do not simply function for species identity. These results suggest that male web-building spiders employ a phylogenetically conserved vibra...
Flexibility and Versatility, 2009
Functional Ecology, 2014
1. The astounding diversity of animal coloration is indicative of a wide variety of selection pre... more 1. The astounding diversity of animal coloration is indicative of a wide variety of selection pressures. Despite great interest in adaptive function, detailed understanding of the constituent elements of colour traits is lacking for many systems. Such information is important in allowing more accurate appraisals of colour variation and its potential production costs. 2. In this study, we 'dissect' the dorsal colour of crab spiders (Thomisidae) to examine the mechanistic basis of a polyphenic colour trait. These spiders possess the ability to alter reflectance in the ultraviolet (UV), violet and blue wavelengths, changing their colour within days. We investigate and compare the proximate mechanistic basis of colour production in multiple phenotypes of three species using histology and spectrophotometry. 3. Our analyses indicate that the spider cuticle is not equivalently transparent to light across the spectrum (300-700 nm)as previously arguedand contributes to colour variation. UV light is reflected from guanine crystals, present in storage cells ventral to the hypodermis. The crystals are exposed through a partially UV-transmitting hypodermis and cuticle. Variation from white to yellow is likely mediated through pigments/crystals present in different oxidative stages in the hypodermal cells. 4. Simple mechanistic changes are therefore necessary to produce the observed variation, and likely underlie the evolutionary and ontogenetic lability of this trait. Our findings imply that either a UV-reflective abdomen was the ancestral state for crab spiders, or, if pre-dated by UV-absorbent hypodermal pigments, the evolution of UV reflection has only involved the exposure of underlying guanine crystals through an otherwise clear hypodermis.
Female reproductive status can have strong selective effects on male mating strategies due to the... more Female reproductive status can have strong selective effects on male mating strategies due to the threat of sperm competition, which may explain why males prefer virgin over mated females. However, in mating systems with female multiple mating rates and mating plugs, males should not only respond to the risk but also to the level of sperm competition and should be sensitive to the interference from mating plugs. In the orb-web spider Argiope keyserlingi, females possess paired sperm-storage organs facilitating separate sperm storage from different males. Males are limited to 2 copulations due to mutilation of their paired genitals (pedipalps). By conducting binary choice experiments, we tested whether males of different mating status can distinguish between females that mated with 1 or 2 males and whether single-mated males discriminate between single-mated females with matched or unmatched virgin genital openings. Furthermore, we investigated whether males adapt their mating strategies to the intensity of sperm competition by providing males with varying qualities of females in their immediate vicinity. Our results demonstrated that males are sensitive to the level of sperm competition and preferred single-mated females over double-mated females. However, they failed to identify singlemated females whose virgin genital opening matched their unused pedipalp, which is required due to their fixed ipsilateral insemination. Surprisingly, males never mated twice with the same female independently of the quality of surrounding females. This suggests that the benefits from searching and mating with a different female are greater than the benefits of monopolizing the female by mating twice with her.
Courtship signals are expected to be consistent within but vary between males of different qualit... more Courtship signals are expected to be consistent within but vary between males of different qualities. Such traits are, therefore, predicted to exhibit high repeatability. However, studies have shown that courtship behaviors vary greatly in their within-individual repeatability, resulting in substantial variation in their ability to reflect male quality. This has implications for the evolution of female mate choice and courtship communication, as low levels of repeatability may reflect courtship signals that do not provide accurate quality information to females. In this article, we tested whether male courtship shuddering in the tropical orb-web spider, Argiope radon, influences female mate choice. We also tested whether male shudder performance reflects male phenotypic condition and is repeatable. We found that male shudder performance and condition predicted female latency to move onto the mating thread, a measure of mate preference. Aspects of male shudder performance were positively correlated with male body condition. Further, we found surprisingly high levels of repeatability in male courtship shuddering, ranking among the highest levels recorded to date for courtship behavior. We suggest that male courtship shuddering functions as an important indicator of male quality, with strong potential to respond to selection.
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Papers by Marie Herberstein
spiders, UV– spiders produced less excitation of the UV- photoreceptors in honeybees and blue tits, which translated into a reduced UV-receptor contrast and a reduced overall colour contrast between UV– spiders and daisy petals. Our results reveal that a clean physical elimination of reflection in the UV range affects perception in predators and prey and ultimately changes the behaviour of prey.
spiders, UV– spiders produced less excitation of the UV- photoreceptors in honeybees and blue tits, which translated into a reduced UV-receptor contrast and a reduced overall colour contrast between UV– spiders and daisy petals. Our results reveal that a clean physical elimination of reflection in the UV range affects perception in predators and prey and ultimately changes the behaviour of prey.