Mark A Elgar

• PhD
• Professor at University of Melbourne

Symbiotic relationships shape ecological communities and often involve more than two species. Yet few experimental studies examine the impact of symbioses involving three species, particularly any mediating role of third parties, and none involving symbioses of predators. We investigated experimentally the synergistic and antagonistic fitness effec...

Juvenile diet can profoundly affect subsequent adult development, morphology and reproductive investment. Yet, little is known about how juvenile diet affects adult investment into chemical‐based sexual signalling, perhaps due to the historical assumption that pheromone production is not costly. We explored how juvenile diet influenced the reproduc...

Nature provides a rich source of information for the design of novel materials; yet there remain significant challenges in the design and manufacture of materials that replicate the form, function, and sustainability of biological solutions. Here, we identify key challenges and promising approaches to the development of materials informed by biolog...

The consequences of sub-lethal levels of ambient air pollution are underestimated for insects, for example, the accumulation of particulate matter on sensory receptors located on their antennae may have detrimental effects to their function. Here we show that the density of particulate matter on the antennae of houseflies (Musca domestica) collecte...

Previous studies on stationary prey have found mixed results for the role of a glossy appearance in predator avoidance—some have found that glossiness can act as warning coloration or improve camouflage, whereas others detected no survival benefit. An alternative untested hypothesis is that glossiness could provide protection in the form of dynamic...

Background Theory predicts that the level of escalation in animal contests is associated with the value of the contested resource. This fundamental prediction has been empirically confirmed by studies of dyadic contests but has not been tested experimentally in the collective context of group-living animals. Here, we used the Australian meat ant Ir...

Theory predicts that males and females of dioecious species typically engage in an evolutionary sexual conflict over the frequency and choice of mating partner. Female sexual cannibalism, a particularly dramatic illustration of this conflict, is widespread in certain animal taxa including spiders. Nevertheless, females of some funnel weaving spider...

Diverse animals including snakes, spiders and phasmids sway in response to abiotic and biotic factors. Recent research on swaying in phasmids suggest they may adopt distinctive swaying to reduce detection from predators. This view was recently challenged, by interpreting swaying behavior as serving a balancing function related to postural sway and...

Darwin argued a role for sexual selection in the evolution of male sensory structures, including insect antennae, the strength of which will depend upon the importance of early arrival at receptive females. There is remarkable variation in the nature and degree of sexual dimorphism in moth antennae, with males of some species having spectacular, fe...

Spider webs are iconic examples of extended phenotypes that are remarkably plastic across different environments. Orb webs are not only effective traps for capturing prey, but can also provide information to potential mates and, in some cases, potential predators and prey through silk-based chemicals. As with regular phenotypic traits, variability...

Sexual signalling is a key feature of reproductive investment, yet the effects of immune system activation on investment into chemical signalling, and especially signal receiver traits such as antennae, are poorly understood. We explore how upregulation of juvenile immunity affects male antennal functional morphology and female pheromone attractive...

Bioinspiration and biomimetics is a rapidly growing field where insights from biology are used to solve current design challenges. Nature provides an abundance of inspiration to draw upon, yet biological information is under-exploited due to a concerning lack of engagement from biologists. To assess the extent of this problem, we surveyed the curre...

Captive breeding programmes are key to many threatened species reintroduction strategies but could potentially be associated with adaptations to captivity that are maladaptive in their natural habitat. Despite the importance of sensory ecology to biological fitness, few studies explore sensory system adaptations to captivity. Captive environments a...

Alarm pheromones, which have been documented in many species of ants, are thought to elicit responses related to aggressive or defensive behaviour. The volatile odour 6‐methyl‐5‐hepten‐2‐one is described as an alarm pheromone in several species of ants, including the Australian meat ant, Iridomyrmex purpureus. The alarm pheromone is released by dis...

Animal colour patterns remain a lively focus of evolutionary and behavioural ecology, despite the considerable conceptual and technical developments over the last four decades. Nevertheless, our current understanding of the function and efficacy of animal colour patterns remains largely shaped by a focus on stationary animals, typically in a static...

The perception of cues and signals in visual, olfactory and auditory modalities underpins all animal interactions and provides crucial fitness-related information. Sensory organ morphology is under strong selection to optimize detection of salient cues and signals in a given signalling environment, the most well-studied example being selection on e...

The introduction of artificial light at night (ALAN) into natural and urbanised landscapes is a known and highly pervasive disruptor of invertebrate communities. However, the effect of variation in intensity and spectra of ALAN on invertebrate communities inhabiting different spatial niches is little understood. Further, the remarkable ability of A...

Theoretical models predict that virgin females at risk of not mating should strategically adjust their signalling investment as they age, with older, virgin females investing more to attract males. We explored how adult age influences the ‘calling’ (pheromone-releasing) behaviour of virgin female gumleaf skeletonizer moths, Uraba lugens, over four...

Juvenile population density has profound effects on subsequent adult development, morphology and reproductive investment. Yet, little is known about how the juvenile social environment affects adult investment into chemical sexual signalling. Male gumleaf skeletonizer moths, Uraba lugens, facultatively increase investment into antennae (pheromone r...

Juvenile population density has profound effects on subsequent adult development, morphology and reproductive investment. Yet, little is known about how the juvenile social environment affects adult investment into chemical sexual signalling. Male gumleaf skeletonizer moths, Uraba lugens, facultatively increase investment into antennae (pheromone r...

Males of many moths possess scent organs, ranging from simple scales and hair-tufts to complex glands. Males of the gregarious beet webworm Loxostege sticticalis (Lepidoptera: Crambidae) display their ventroposterior brushes (VPBs), located on the eighth abdominal sternite, toward adjacent females and usually maintain this posture until sexually re...

Our understanding of the extraordinary mechanical and physico-chemical properties of spider silk is largely confined to the fibers produced by orb-weaving spiders, despite the diversity of foraging webs that occur across numerous spider families. Crab spiders (Thomisidae) are described as ambush predators that do not build webs, but nevertheless us...

Our understanding of the extraordinary mechanical and physico-chemical properties of spider silk is largely confined to the fibers produced by orb-weaving spiders, despite the diversity of foraging webs that occur across numerous spider families. Crab spiders (Thomisidae) are described as ambush predators that do not build webs, but nevertheless us...

Our understanding of the extraordinary mechanical and physico‑chemical properties of spider silk is largely confined to the fibers produced by orb‑weaving spiders, despite the diversity of foraging webs that occur across numerous spider families. Crab spiders (Thomisidae) are described as ambush predators that do not build webs, but nevertheless us...

Non-injurious, collective ritualized displays may have evolved in some species of ants as a means of resolving contests for key resources, without causing a drain in worker numbers through injury. Colonies of the Australian meat ant, Iridomyrmex purpureus, deploy numerous workers to engage in collective displays, which are widely understood to be i...

Carrion-feeding flies use odours emanating from the decomposing corpse as cues for oviposition and are described as generalists because the larvae feed on the corpses of diverse species. Whereas several features of the corpse may influence the oviposition choices of these flies, it is not known whether there is a preference for a particular species...

Many animals improve their foraging success by producing signals that exploit the sensory biases of potential prey, but the specific properties that make these sensory traps effective remain unclear. We combine field experiments with phylogenetic comparative analyses to investigate the visual luring properties of different signal designs in web‐bui...

Signals of resource-holding potential in dyadic (one-on-one) contests are relatively straightforward, typically reflected in the attributes of the individual, including body size and resource ownership. However, conveying this information is considerably more complex in social species: the outcome of collective contests will be influenced by both i...

The wide variety of colours exhibited by animals have long been a source of fascination and conjecture, but procedural and theoretical limitations have reduced our ability to explore the wide range of possible relationships between colour traits and environmental variables. In this presentation, we shared preliminary results from our study, emplo...

Task allocation ensures a high level of organization within social insect colonies. Workers reveal their task assignment through cuticular hydrocarbon (CHC) signals. The source and chemical composition of these signals are largely unknown. We ask whether task recognition signals are located on particular body parts of workers of Australian meat ant...

Stomach bot flies (Calyptratae: Oestridae, Gasterophilinae) are obligate endoparasitoids of Proboscidea (i.e. elephants), Rhinocerotidae (i.e. rhinos) and Equidae (i.e. horses and zebras, etc.), with their larvae developing in the digestive tract of hosts with very strong host specificity. They represent an extremely unusual diversity among diptera...

The reach of artificial light at night (ALAN) is growing rapidly around the globe, including the increasing use of energy‐efficient LED lights. Many studies document the physiological costs of light at night, but far fewer have focused on the potential benefits for nocturnal insectivores and the likely ecological consequences of shifts in predator–...

Studies of sexual selection that occurs prior to mating have focussed on either the role of armaments in intra-sexual selection, or extravagant signals for inter-sexual selection. However, Darwin suggested that sexual selection may also act on ‘organs of sense’, an idea that seems to have been largely overlooked. Here, we refine this idea in the co...

Chemical communication involves the production, transmission, and perception of odors. Most adult insects rely on chemical signals and cues to locate food resources, oviposition sites or reproductive partners and, consequently, numerous odors provide a vital source of information. Insects detect these odors with receptors mostly located on the ante...

Group-living behavior is taxonomically widespread but rare in spiders. The conventional view is that the main pathways to group-living in spiders are either sub-social, where extended maternal care leads to prolonged sibling association; or communal living, where individuals aggregate to exploit a common resource. Female egg-sac guarding behavior o...

R script for NMDS and average silhouette analyses. (TXT)

Detailed methods of TE-AFLP DNA fingerprinting. (DOCX)

The raw binary matrix of AFLP markers of group-living A. cf. fissifrons. (CSV)

The raw binary matrix of AFLP markers of solitary N. trigonum. (CSV)

The raw binary matrix of AFLP markers of group-living A. miniaceus. (CSV)

The raw binary matrix of AFLP markers of solitary A. fasciatus. (CSV)

Light is fundamental to biological systems, affecting the daily rhythms of bacteria, plants, and animals. Artificial light at night (ALAN), a ubiquitous feature of urbanization, interferes with these rhythms and has the potential to exert strong selection pressures on organisms living in urban environments. ALAN also fragments landscapes, altering...

Lateralisation of biological form and function are well known for vertebrates and are being increasingly documented among invertebrates in recent years. Behavioural lateralisation in insects, together with asymmetrical distributions of antennal sensilla, has been linked to the communication challenges faced by social, but not solitary, insects. Rec...

Social insects construct nests that protect their brood and food resources from both the physical environment and natural enemies. Stingless bees use plant‐derived resins, mixed with wax to form propolis, in the construction of their nests, and these products can be effective sources of defense against natural enemies, including ants. However, it i...

Division of labour in social insect colonies is facilitated in two ways: through temporal sharing of tasks or by morphologically specialised castes. In casteless species, colony defence is maintained by morphologically indistinct workers, who lack the obvious defensive specialisation of polymorphic species. Discrimination of intruders is carried ou...

The Jarman–Bell principle seeks to explain why smaller herbivore species tend to select higher-quality forage (high protein and high fiber digestibility) than larger herbivore species. This principle may also provide insight into intraspecific differences in resource use in species with pronounced sexual size dimorphism. We examined the relationshi...

The elaborate bipectinate antennae of male moths are thought to increase their sensitivity to female sex pheromones, and so should be favoured by selection. Yet simple filamentous antennae are the most common structure among moths. The stereotypic arrangements of scales on the surface of antennae may resolve this paradox. We use computational fluid...

The Lord Howe Island stick insect (Dryococelus australis) is one of the world’s rarest insects. However, the opportunity to reintroduce the species to Lord Howe Island, and commence the path to recovery, may occur within the next 5 years. Understanding the insect’s host plant and habitat preferences on Lord Howe Island is critical to maximising the...

Leaders in democratic societies emerge by dint of followers, but the traits that determine who those leaders are, and the underlying mechanisms maintaining leadership, remain largely unknown. Models suggest a link between leadership and knowledge is important for group decisions, with more informed individuals guiding the uninformed majority. In la...

The variation in animal coloration patterns has evolved in response to different visual strategies for reducing the risk of predation. However, the perception of animal coloration by enemies is affected by a variety of factors, including morphology and habitat. We use the diversity of Australian chrysomeline leaf beetles to explore relationships of...

Developmental plasticity provides individuals with a distinct advantage when the reproductive environment changes dramatically. Variation in population density, in particular, can have profound effects on male reproductive success. Females may be easier to locate in dense populations, but there may be a greater risk of sperm competition. Thus, male...

The functional importance of animal colouration has long been of interest to ecologists, but it is only the relatively recent accessibility of robust digital photography techniques that has seen colour trait-environment associations explored on a global scale. However, the influence of preservation method is not often considered, with many studies...

The notion that behavioral differences between the sexes are innate and immutable does not hold up under scrutiny

The use of prey-attracting allomones is likely to be an effective foraging strategy for sit-and-wait predators. Despite this, the production and efficacy of such allomones have rarely been documented. Previous investigations into the chemical composition of spider silk have revealed the presence of a number of potential allomone chemicals such as t...

Pheromones are chemical compounds used to transmit information between individuals of the same species. Pheromone composition is influenced by both genetic and environmental factors. Numerous studies, predominately of insects, have demonstrated a role for diet in pheromone expression. The chemical composition of spider web-silk varies with diet and...

Significance Communication is central to group living: Individuals use signals to identify each other and coordinate tasks. Surprisingly, little is known about how these communication systems change as social behavior evolves, particularly during the transition between solitary and group living. This study shows that, as sociality is gained and los...

Sexual selection theory predicts that female choice may favour the evolution of elaborate male signals. Darwin also suggested that sexual selection can favour elaborate receiver structures in order to better detect sexual signals, an idea that has been largely ignored. We evaluated this unorthodox perspective by documenting the antennal lengths of...

Facultative parthenogenetic species, in which females can alternate between sex and parthenogenesis, are useful models to investigate the costs and benefits of sex and parthenogenesis, an ongoing issue in biology. The necessary empirical studies comparing the outcomes of alternative reproductive modes on life history traits are rare and focus mainl...

Gregariousness is a common feature in aposematic insect prey and offers the additional benefit of enhancing the effectiveness of their toxic defences. Aggregations of the aposematic larvae of two species of leaf beetles, Paropsis atomaria and Paropsisterna variicollis, occur together on the same Eucalyptus trees over spring and summer. Conventional...

Diet is arguably the most significant environmental factor shaping chemical signals in animals. In rare cases, dietary components are converted directly into pheromones or signature mixtures but more generally variation in an individual's diet influences their overall condition and thus capacity to synthesize the signal. Typically, diet is variable...

The quality of many animal signals varies, perhaps through their use in different contexts or by representing an adaptive response to reduce the risk of exploitation. Spiders of the orb weaver genus Argiope add linear, cruciate or circular silk structures to their orb webs, creating inter- and intra-specific polymorphic visual signals. Different de...

Background Genital diversity may arise through sexual conflict over polyandry, where male genital features function to manipulate female mating frequency against her interest. Correlated genital evolution across animal groups is consistent with this view, but a link between genital complexity and mating rates remains to be established. In sexually...

Foraging animals regulate their intake of macronutrients such as carbohydrates and proteins. However, regulating the intake of these two macronutrients can be constrained by the nutrient content of available food sources. Compensatory foraging is a method to adjust nutrient intake under restricted nutrient availability by preferentially exploiting...

Signalling is necessary for the maintenance of interspecific mutualisms but is vulnerable to exploitation by eavesdropping. While eavesdropping of intraspecific signals has been studied extensively, such exploitation of interspecific signals has not been widely documented. The juvenile stages of the Australian lycaenid butterfly, Jalmenus evagoras,...

Most animals are under strong selection to avoid predation, and several strategies have evolved in response to this selection. The developmental change in colour patterns of toxin-protected chrysomeline larvae provides a system to investigate the potential costs and benefits of conspicuous coloration development in animals. Field experiments in whi...

Parthenogenetic reproduction is taxonomically widespread and occurs through various cytological mechanisms, which have different impact on the genetic variation of the offspring. Extatosoma tiaratum is a facultatively parthenogenetic Australian insect (Phasmatodea), in which females oviposit continuously throughout their adult lifespan irrespective...

Males can typically increase their lifetime reproductive success by mating with multiple females. However, recent studies across a broad range of species have demonstrated physiological constraints on male multiple mating. In this study, we investigate male mating capacity in Extatosoma tiaratum, a facultative parthenogenetic phasmatid. Sperm limit...

Social insects use cuticular hydrocarbons (CHCs) to convey different social signals, including colony or nest identity. Despite extensive investigations, the exact source and identity ofCHCs that act as nest-specific identification signals remain largely unknown. Perhaps this is because studies that identify CHC signals typically use organic solven...

Specialist species show stronger resource selection, narrower niches and lower niche overlap than generalist species. We examined ecological specialisation with respect to habitat selection in a macropodid community comprising the western grey kangaroo Macropus fuliginosus, red-necked wallaby M. rufogriseus and swamp wallaby Wallabia bicolor in the...

Keywords: aggressive spillover mate size difference mating personality sexual cannibalism voracity Intersexual agonistic encounters prior to mating are thought to result from the 'spillover' of the advantages of a voracious personality within a foraging context that is maladaptive in a mating context. We tested this idea by examining the repeatabil...

There is emerging interest in drawing insights from evolutionary biology to understand the nature of human leadership as a position within a social system. This perspective assumes that natural selection favors individuals who recognize leadership qualities that will benefit both leaders and followers. Physical stature, in particular, is frequently...

Many theories attempt to explain patterns of community organisation among large herbivores. We explored the role of body size, diet type and residence time on habitat use in a community comprising four metatherians (western grey kangaroo, Macropus fuliginosus; eastern grey kangaroo, M. giganteus; red-necked wallaby, Notamacropus rufogriseus; swamp...

Foraging herbivores face twin threats of predation and parasite infection, but the risk of predation has received much more attention. We evaluated, experimentally, the role of olfactory cues in predator and parasite risk assessment on the foraging behaviour of a population of marked, free-ranging, red-necked wallabies (Macropus rufogriseus). The w...

Pheromones, arguably the most ubiquitous mode of animal communication, are determined by both genetic and environmental factors. Recent evidence suggests that diet may be an important determinant of pheromone variation, which may both enhance and reduce the reliability of the chemical signal. We investigated experimentally the impact of population...

Several species of stick insects sway from side to side when blown by wind. Although anecdotal evidence suggests this is a camouflage strategy to resemble wind-blown vegetation, this behavior has never been experimentally investigated. We evaluated the responses of female Macleay’s Spectre (Extatosoma tiaratum) to wind cues and quantified the degre...

For dioecious animals, reproductive success typically involves an exchange between the sexes of signals that provide information about mate location and quality. Typically, the elaborate, secondary sexual ornaments of males signal their quality, while females may signal their location and receptivity. In theory, the receptor structures that receive...

Sperm competition studies typically identify copulation duration as an important predictor of paternity as it may determine the quantity of sperm transferred and thus paternity success. This study explores the relationship between copulation duration, male body size, male age and sperm transfer in the golden orb-weaving spider, Nephila edulis. Pate...

The challenges of maintaining cohesion while making collective decisions in social or aggregating insects can result in the emergence of a leader or leaders. Larval aggregations of the steel-blue sawfly Perga affinis forage nocturnally, and some larvae lead the aggregation on foraging trips more often than expected by chance. We investigated the re...

Integrating the insights derived from both phylogenetic and experimental approaches offers a more complete understanding of evolutionary patterns and processes, yet it is rarely a feature of investigations of the evolutionary significance of trait variation. We combine these approaches to reinterpret the patterns and processes in the evolution of f...

Pheromones are intraspecific chemical signals. They can have profound effects on the behaviour and/or physiology of the receiver, and it is still common to hear pheromones described as controlling of the behaviour of the receiver. The discussion of pheromonal control arose initially from a close association between hormones and pheromones in the co...

Wildfires cause enormous damage worldwide, particularly in Victoria, Australia, with growing populations in fire-prone ecosystems. Broad-scale prescribed burning is an established, yet controversial, wildfire management policy in Victoria and Australia. But does broad-scale prescribed burning reduce fire damage? The answer depends on how damage is...

Effective communication requires precise signals that can be detected reliably against background noise. To demonstrate an impact of background noise on social signals, it is necessary to distinguish its effects on signal reception from that on behaviour more generally. The ability of workers of Iridomyrmex purpureus (Smith, 1858) (Hymenoptera: For...

Body size affects key life-history parameters including dietary requirements and predation risk. We examined these effects on diel habitat use in a community of three sexually-dimorphic macropodid marsupial species: western grey kangaroo Macropus fuliginosus, red-necked wallaby M. rufogriseus and swamp wallaby Wallabia bicolor. In particular, our s...

Abstract Effective communication requires reliable signals and competent receptors. Theoretical and empirical accounts of animal signaling focus overwhelmingly on the capacity of the signaler to convey the message. Nevertheless, the intended receiver's ability to detect a signal depends on the condition of its receptor organs, as documented for hum...

Promiscuity is frequently used to describe animal mating behaviour, and especially to describe multiple mating by females. Yet this use of the term is incorrect, perhaps reflecting an erroneous adoption of common language to pique reader interest. We evaluated the patterns of use and misuse of the word 'promiscuity' in a representative journal of a...

Chalcidoid wasps represent one of the most speciose superfamilies of animals known, with ca. 23,000 species described of which many are parasitoids. They are extremely diverse in body size, morphology and, among the parasitoids, insect hosts. Parasitic chalcidoids utilise a range of behavioural adaptations to facilitate exploitation of their divers...

The relationship between female mating preferences and sex allocation has received considerable theoretical and empirical support. Typically, choosier females adjust their progeny sex ratio towards sons, who inherit the attractive traits of their father. However, in species with paternal genome elimination, where male sperm do not contain the pater...

Confirmation bias is a tendency of people to interpret information in a way that confirms their expectations. A long recognized phenomenon in human psychology, confirmation bias can distort the results of a study and thus reduce its reliability. While confirmation bias can be avoided by conducting studies blind to treatment groups, this practice is...

PRISMA 2009 Checklist. (DOC)