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January 1996 - June 1999
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Publications (149)
Non‐ecological speciation is a common mode of speciation, which occurs when allopatric lineages diverge in the absence of pronounced ecological differences. Yet, relative to other speciation mechanisms, non‐ecological speciation remains understudied. Numerous damselfly clades are characterised as non‐adaptive radiations (the result of several round...
Animal coloration has long been predicted to vary across geographic and climatic gradients in accordance with a long‐standing ecogeographical rule. But further to his widely supported predictions that melanin pigmentation increases towards the Equator, Gloger observed that reds and yellows are more vivid in warm regions and thus more prevalent at l...
Non-ecological speciation is a common mode of speciation which occurs when allopatric lineages diverge in the absence of pronounced ecological differences. Yet, relative to other speciation mechanisms, non-ecological speciation remains understudied. Numerous damselfly clades are characterized as non-adaptive radiations (the result of several rounds...
Mutualistic interactions between species are widespread and important for community structure and ecosystem function. In a changing environment, the proximate mechanisms that maintain mutualisms affect their stability and susceptibility to perturbation. In ant‐plant mutualisms, ants defend their host plants against herbivores or competing plants in...
Understanding species distributions and predicting future range shifts requires considering all relevant abiotic factors and biotic interactions. Resource competition has received the most attention, but reproductive interference is another widespread biotic interaction that could influence species ranges. Rubyspot damselflies (Hetaerina spp.) exhi...
Smoky rubyspot damselflies (Hetaerina titia Drury, 1773) are one of the most commonly encountered odonates along streams and rivers on both slopes of Central America and the Atlantic drainages in the United States and southern Canada. Owing to their highly variable wing pigmentation, they have become a model system for studying sexual selection and...
Interference competition can drive species apart in habitat use through competitive displacement in ecological time and agonistic character displacement (ACD) over evolutionary time. As predicted by ACD theory, sympatric species of rubyspot damselflies (Hetaerina spp.) that respond more aggressively to each other in staged encounters differ more in...
We explore how integrating behavioural ecology and macroecology can provide fundamental new insight into both fields, with particular relevance for understanding ecological responses to rapid environmental change. We outline the field of macrobehaviour, which aims to unite these disciplines explicitly, and highlight examples of research in this spa...
Translocation programs for endangered mammalian carnivores face numerous challenges, including the potential for lethal interactions between releasees and resident conspecifics. Here we evaluate whether familiarizing residents with the scent of releasees might be an effective strategy for reducing aggression following Tasmanian devil (Sarcophilus h...
Translocation programmes for endangered species typically focus on a single species, but in areas where little native habitat remains, it may be necessary to translocate multiple species to the same sites. Interactions between translocated species, such as predation and competition, are among the factors that need to be considered when planning mul...
Damselflies and dragonflies (Order: Odonata) play important roles in both aquatic and terrestrial food webs and can serve as sentinels of ecosystem health and predictors of population trends in other taxa. The habitat requirements and limited dispersal of lotic damselflies make them especially sensitive to habitat loss and fragmentation. As such, l...
As species' ranges shift in response to human‐induced global changes, species interactions are expected to play a large role in shaping the resultant range dynamics and, subsequently, the composition of modified species assemblages. Most research on the impact of species interactions on range dynamics focuses on the effects of trophic interactions...
This research-level text documents the latest advances in odonate biology and relates these to a broader ecological and evolutionary research agenda. Despite being one of the smallest insect orders, dragonflies offer a number of advantages for both laboratory and field studies. In fact, they continue to make a crucial contribution to the advancemen...
Group-living spiders are rare, and can be divided into multiple subcategories based on their tolerance of group mates. While social spiders are cooperative, colonial spiders are often antagonistic towards conspecifics. We examined colony dynamics in a colonial species, Philoponella republicana (Simon, 1891), focusing on aggressive behaviors to furt...
The damselflies Hetaerininae, a subfamily of Calopterygidae, comprise four genera distributed from North to South America: Hetaerina, Mnesarete, Ormenophlebia and Bryoplathanon. While several studies have focused on the intriguing behavioral and morphological modifications within Hetaerina, little of the evolutionary history of the group is well un...
As species' ranges shift in response to human-induced global changes, species interactions are expected to play a large role in shaping the resultant range dynamics and, subsequently, the composition of modified species assemblages. Most research on the impact of species interactions on range dynamics focuses on the effects of trophic interactions...
Theorists have identified several mechanisms through which species that compete exploitatively for resources could coexist. By contrast, under the current theory, interference competitors could coexist only in rare circumstances. Yet, some types of interference competition, such as interspecific territoriality, are common. This mismatch between the...
Coexistence of competing species in the same foraging guild has long puzzled ecologists. In particular, how do small subordinate species persist with larger dominant competitors? This question becomes particularly important when conservation interventions, such as reintroduction or translocation, become necessary for the smaller species. Exclusion...
Interspecific territoriality has complex ecological and evolutionary consequences. Species that interact aggressively often exhibit spatial or temporal shifts in activity that reduce the frequency of costly encounters. We analyzed data collected over a 13-year period on 50 populations of rubyspot damselflies (Hetaerina spp.) to examine how rates of...
1. Trade-offs between male mating success and survival are the basis of alternative male reproductive tactics.
2. Adult male Greta morgane butterflies acquire protective pyrrolizidine alkaloids (PAs) from plants and use PA-derived pheromones to attract females. Adult females acquire PAs from male spermatophores, thereby obtaining chemical defence a...
Charles Darwin would be pleased to know that elementary school children in states that have adopted the Next Generation Science Standards (NGSS) are expected to demonstrate their understanding of several core evolutionary concepts, including trait variation and inheritance, fossils and extinct organisms, common ancestry, natural selection, and adap...
Evolution by natural selection is key to understanding life and of considerable practical importance in public health, medicine, biotechnology, and agriculture. The Next Generation Science Standards (NGSS) include natural selection among several evolutionary concepts that all third-graders should know. This article explores a novel approach to deve...
Behavioral interference between species can influence a wide range of ecological and evolutionary processes. Here we test foundational hypotheses regarding the origins and maintenance of interspecific territoriality, and evaluate the role of interspecific territoriality and hybridization in shaping species distributions and transitions from parapat...
Costly interactions between species that arise as a by-product of ancestral similarities in communication signals are expected to persist only under specific evolutionary circumstances. Territorial aggression between species, for instance, is widely assumed to persist only when extrinsic barriers prevent niche divergence or selection in sympatry is...
Most studies on the processes driving evolutionary diversification highlight the importance of genetic drift in geographical isolation and natural selection across ecological gradients. Direct interactions among related species have received much less attention, but they can lead to character displacement, with recent research identifying patterns...
Many interspecifically territorial species interfere with each other reproductively, and in some cases, aggression towards heterospecifics may be an adaptive response to interspecific mate competition. This hypothesis was recently formalised in an agonistic character displacement (ACD) model which predicts that species should evolve to defend terri...
Behavioral interference between species can influence a wide range of ecological and evolutionary processes. Here we test foundational hypotheses regarding the origins and maintenance of interspecific territoriality, and evaluate the role of interspecific territoriality and hybridization in shaping species distributions and transitions from parapat...
Reintroduction programs that release endangered species back into areas from which they have been extirpated rarely take competitive interactions between species into account. The endangered Pacific pocket mouse (Perognathus longimembris pacificus) is being reintroduced to parts of its former range where multiple species of native rodents have over...
Research on territoriality has barely progressed beyond the descriptive stage in most aquatic insects, but some territorial species have been studied intensively and served as model organisms for testing certain aspects of evolutionary theory. After providing a brief introduction to territoriality in general, I review the taxonomic distribution and...
Field investigations of phenotypic variation in free‐living organisms are often limited in scope owing to time and funding constraints. By collaborating with online communities of amateur naturalists, investigators can greatly increase the amount and diversity of phenotypic data in their analyses while simultaneously engaging with a public audience...
Reproductive interference is widespread, despite the theoretical expectation that it should be eliminated by reproductive character displacement (RCD). A possible explanation is that females of sympatric species are too similar phenotypically for males to distinguish between them, resulting in a type of evolutionary dilemma or catch-22 in which rep...
Incomplete reproductive isolation between related species of birds at contact zones is increasingly being documented. Such hybridization typically occurs between sister taxa that diverged in relatively recent times, and hybrids are most often identified based on their intermediate phenotypic characteristics and, increasingly, through genetic admixt...
Field investigations of phenotypic variation in free living organisms are often limited in scope owing to time and funding constraints. By collaborating with online communities of amateur naturalists, investigators can greatly increase the amount and diversity of phenotypic data in their analyses while simultaneously engaging with a public audience...
In nonterritorial damselflies, females often come in multiple color morphs, perhaps because females with rare colors experience reduced sexual harassment, and thus have a frequency‐dependent fitness advantage, compared to females of the most common color morph, but such polymorphisms are rare in territorial species. We consider three hypotheses to...
The role of interspecific aggression in structuring ecological communities can be important to consider when reintroducing endangered species to areas of their historic range that are occupied by competitors. We sought to determine which species is the most serious interference competitor of the endangered Pacific pocket mouse, Perognathus longimem...
Much ecological and evolutionary theory predicts that interspecific interactions often drive phenotypic diversification and that species phenotypes in turn influence species interactions. Several phylogenetic comparative methods have been developed to assess the importance of such processes in nature; however, the statistical properties of these me...
Much ecological and evolutionary theory predicts that interspecific interactions often drive phenotypic diversification and that species phenotypes in turn influence species interactions. Several phylogenetic comparative methods have been developed to assess the importance of such processes in nature; however, the statistical properties of these me...
Behavioral interference between species, such as territorial aggression, courtship, and mating, is widespread in animals. While aggressive and reproductive forms of interspecific interference have generally been studied separately, their many parallels and connections warrant a unified conceptual approach. Substantial evidence exists that aggressiv...
Much ecological and evolutionary theory predicts that interspecific interactions often drive phenotypic diversification and that species phenotypes in turn influence species interactions. Several phylogenetic comparative methods have been developed to assess the importance of such processes in nature; however, the statistical properties of these me...
Differences in color vision can play a key role in an organism’s ability to perceive and interact with the environment across a broad range of taxa. Recently, species have been shown to vary in color vision across populations as a result of differences in regulatory sequence and/or plasticity of opsin gene expression. For decades, biologists have b...
Interspecific territoriality may play an important role in structuring ecological communities, but the causes of this widespread form of interference competition remain poorly understood. Here, we investigate the phenotypic, ecological and phylogenetic correlates of interspecific territoriality in wood warblers (Parulidae). Interspecifically territ...
Understanding how phenotypic plasticityevolves and in turn affects thecourse of evolution is a major challenge in modern biology.By definition, biological species are reproductively isolated, but many animals fail to distinguish between conspecifics and closely related heterospecifics. In some cases, phenotypic plasticity may interfere with species...
Interspecific territoriality occurs when individuals of different species fight over space, and may arise spontaneously when populations of closely related territorial species first come into contact. But defence of space is costly, and unless the benefits of excluding heterospecifics exceed the costs, natural selection should favour divergence in...
The decision rules that animals use for distinguishing between conspecifics of different age and sex classes are relevant for understanding how closely related species interact in sympatry. In rubyspot damselflies (Hetaerina spp.), the red wing coloration of mature males is hypothesized to be a key trait for sex recognition and competitor recogniti...
Manakins (Pipridae) are well know for elaborate male sexual displays and ornate plumage coloration, both of which are thought to have evolved as a consequence of lekking breeding, the prevalent mating system in the family. Less attention has been paid to a handful of ‘drab’ manakin species, in which sexual dimorphism appears to be reduced or absent...
Traits that mediate intraspecific social interactions may overlap in closely related sympatric species, resulting in costly between-species interactions. Such interactions have principally interested investigators studying the evolution of reproductive isolation via reproductive character displacement (RCD) or reinforcement, yet in addition to repr...
Bright and/or conspicuous displays of color constitute a major, functionally diverse class of animal signals. Despite the complexities of color production, however, researchers have been largely pre-occupied with understanding how a few select pigments, such as carotenoids, contribute to the honest signaling of mate quality. As a consequence, the f...
Many species roost communally but the proximate causes and ultimate functions of this widespread behavior remain poorly understood. We studied the communal roosts of two undescribed species of harvestmen in the genus Prionostemma Pocock 1903 at a Caribbean rainforest site in southeastern Nicaragua. The species are quite similar in gross morphology...
Situations in which animals preferentially settle in low-quality habitat are referred to as ecological traps, and species that aggregate in response to conspecific cues, such as scent marks, that persist after the animals leave the area may be especially vulnerable. We tested this hypothesis on harvestmen (Prionostemma sp.) that roost communally in...
Sympatric species of coprophagus dung beetles rely on essentially the same resource for provisioning broods, which raises the question of how local species diversity is maintained. Interspecific competition may be mitigated to some extent by large-scale spatial (e.g., habitat type) and temporal (e.g., seasonal) variation in activity. Niche partitio...
Normal development depends on specific genetic and environmental inputs. When environments change, entire populations of organisms may simultaneously express maladaptive phenotypes. Selection in the new environment may gradually restore the ancestral phenotype by favouring alleles that counteract the environmental perturbation. This evolutionary pr...
Competition has always been a cornerstone of evolutionary biology, and aggression is the predominant form of direct competition in animals, but the evolutionary effects of aggression between species are curiously understudied. Only in the past few years, existing theoretical frameworks have been extended to include interspecific aggression, and sig...
Sympatric divergence in traits affecting species recognition can result from selection against cross-species mating (reproductive character displacement, RCD) or interspecific aggression (agonistic character displacement, ACD). When the same traits are used for species recognition in both contexts, empirically disentangling the relative contributio...
'Tradition' has been invoked to explain instances in which animals aggregate repeatedly in the same locations for no apparent reason, but alternative explanations, such as cryptic habitat selection, are difficult to rule out. Distinguishing among these hypotheses requires field experiments. We studied a species of harvestman (Prionostemma sp.) that...
We combine acoustic data, taken in situ, with spectrophotometric and morphometric data, taken from museum specimens, to examine patterns of phenotypic variation in Pogoniulus Tinkerbirds. We seek to find possible divergence, convergence and competitive exclusion by comparing patterns between P.pusillus and P.chrysoconus that differ in their extent...
The waterfall damselfly, Paraphelbia zoe, is distributed in cloud forest areas in the Mexican states of Veracruz, Hidalgo, and San Luis Potosi. We developed twelve microsatellite loci for P. zoe from representative samples from the state of Veracruz. Microsatellites were tested for polymorphism on a panel of 24 individuals. The number of alleles ra...
Hetaerina damselflies are distributed throughout the neotropics. We developed eleven microsatellite loci for the damselfly Hetaerina americana. Microsatellites were tested for polymorphism on a panel of 24 individuals. The number of alleles ranged from 2 to 6, observed heterozygosity from 0.080 to 0.701, and the fixation index from −0.266 to 1.000....
Conspicuous displays of color comprise an enormously diverse and functionally complex class of biological signals. Many of these displays are widely publicized as resulting from chemical colorants known as pigments, which act by selectively "absorbing" part of the light spectrum (Appendix 1). However, the full diversity of animal coloration is just...
We tested the hypothesis that mate choice is responsible for countergradient variation in the sexual coloration of Trinidadian guppies (Poecilia reticulata). The nature of the countergradient pattern is that geographical variation in the carotenoid content of the orange spots of males is counterbalanced by genetic variation in drosopterin productio...
Territorial animals can be expected to distinguish among the types of competitors and noncompetitors that they encounter on a regular basis, including prospective mates and rivals of their own species, but they may not correctly classify individuals of other species. Closely related species often have similar phenotypes and this can cause confusion...
Interspecific territoriality may be adaptive if territories contain depletable resources that are valuable to both species,
but it can also arise as a maladaptive by-product of intraspecific territoriality. In the latter scenario, sympatric species
ought to diverge in ways that reduce interspecific fighting. We studied 4 Hetaerina damselfly species...
Despite decades of intensive research, important discoveries continue to be made about how secondary sexual characters and mate preferences evolve. A general prediction of the mate choice indicator models is that female preferences should evolve in response to changes in the indicator value of male traits. One approach to testing this prediction is...
Sexual selection favors traits that give the bearer an advantage in attracting high-quality mates or competing for them. Such traits can contribute to prezygotic isolation between populations, which is thought to usually be the first step toward speciation. Recent theoretical and empirical research suggests that the prospects for speciation are enh...
Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a patte...
Despite decades of intensive research, important discoveries continue to be made about how secondary sexual characters and mate preferences evolve. A general prediction of the mate choice indicator models is that female preferences should evolve in response to changes in the indicator value of male traits. One approach to testing this prediction is...
In zones of sympatry between closely related species, species recognition errors in a competitive context can cause character displacement in agonistic signals and competitor recognition functions, just as species recognition errors in a mating context can cause character displacement in mating signals and mate recognition. These two processes are...
Sexual selection is thought to be opposed by natural selection such that ornamental traits express a balance between these two antagonistic influences. Phenotypic variation among populations may indicate local shifts in this balance, or that different stable 'solutions' are possible, but testing these alternatives presents a major challenge. In the...
The extent to which interspecific interference competition has contributed to character evolution is one of the most neglected problems in evolutionary biology. When formerly allopatric species come into secondary contact, aggressive interactions between the species can cause selection on traits that affect interspecific encounter rates (e.g. habit...
[Kiffner (2009)][1] questions the comparability of the Pleistocene tar seep records and those derived from predator playback experiments. While we acknowledge that they are not identical, the differences are not sufficient to overturn our inference of sociality in Rancho La Brea (RLB) Smilodon . He
The extent to which interspecific interference competition has contributed to character evolution is one of the most neglected problems in evolutionary biology. When formerly allopatric species come into secondary contact, aggressive interactions between the species can cause selection on traits that affect interspecific encounter rates (e.g. habit...
Despite the important effects of diet and parasite infection on male reproductive behavior, few studies have simultaneously
addressed their influence on intrasexual selection (male–male competition). We examined the synergistic effects of 2 naturally
varying environmental factors, lifetime food intake and infection, with the monogenean parasite Gyr...
The evolution of exaggerated sexual ornamentation is classically thought to proceed as a compromise between opposing vectors of sexual and natural selection. In colour-based ornamentation, as exhibited by guppies (Poecilia reticulata), heightened trait expression may be beneficial in promoting attractiveness, but costly in terms of predation. Oppor...
For many species in nature, a sire's progeny may be distributed among a few or many dams. This poses logistical challenges--typically much greater across males than across females--for assessing means and variances in mating success (number of mates) and reproductive success (number of progeny). Here we overcome these difficulties by exhaustively a...
Inferences concerning the lives of extinct animals are difficult to obtain from the fossil record. Here we present a novel approach to the study of extinct carnivores, using a comparison between fossil records (n=3324) found in Late Pleistocene tar seeps at Rancho La Brea in North America and counts (n=4491) from playback experiments used to estima...
Relatively little attention has been directed towards understanding the impacts of human disturbance on evolutionary processes that produce and maintain biodiversity. Here, we examine the influence of anthropogenic habitat changes on traits typically associated with natural and sexual selection in the little greenbul (Andropadus virens), an African...
Figure showing maximum parsimony phylogeny of giraffe (Giraffa camelopardalis) mtDNA haplotypes, rooted using midpoint rooting
Table showing giraffe sampling localities and sample sizes for mtDNA characterization with resulting mtDNA control region haplotypes
Figure showing minimum evolution phylogeny of giraffe (Giraffa camelopardalis) mtDNA haplotypes, rooted with okapi (Okapia johnstoni)
Table of summary statistics for microsatellite data (381 specimens, all populations and pelage subspecies)
Figure showing maximum parsimony phylogeny of giraffe (Giraffa camelopardalis) mtDNA haplotypes, rooted with okapi (Okapia johnstoni)
Figure showing maximum likelihood phylogeny of giraffe (Giraffa camelopardalis) mtDNA haplotypes, rooted with okapi (Okapia johnstoni)
Tables showing (A) observed and expected heterozygosity, and deviations from Hardy-Weinberg equilibrium in six giraffe subspecific populations, and (B) observed and expected heterozygosity, and deviations from Hardy-Weinberg equilibrium in 16 giraffe populations
Tables showing (A) posterior probability population assignments of 381 Individuals, based on assignment to pelage/subspecies designations using STRUCTURE [19], and (B) subspecies assignment of 381 individuals, based on assignment to pelage/subspecies designations, using multilocus genotypes and Bayesian analysis (Rannala and Mountain method in Gene...
Table of Mantel test of isolation by distance results (correlation of genetic distance (Fst/(1-Fst) with geographic distance)
