Animal Life History Research Articles

Environmental influences on rabbit numbers and control methods in southern New Zealand between 1860 and 1930

AbstractIn the mid‐19th century, European rabbits were released in southern New Zealand and thrived in the dry interior. Landholders recognised the need to understand rabbit behaviour, learned to identify vulnerable stages in the animal's life history and based their eradication programmes on that knowledge. Rabbit numbers changed with shifts in prevailing weather systems, and landholders used different combinations of control and extermination methods in wetter than in drier periods. Large properties needed to employ gangs of rabbiters when herbage was abundant and rabbits were common, but required fewer men when rabbits were scarce.

Behavioral Microbiomics: A Multi-Dimensional Approach to Microbial Influence on Behavior.

The role of microbes as a part of animal systems has historically been an under-appreciated aspect of animal life histories. Recently, evidence has emerged that microbes have wide-ranging influences on animal behavior. Elucidating the complex relationships between host–microbe interactions and behavior requires an expanded ecological perspective, involving the host, the microbiome and the environment; which, in combination, is termed the holobiont. We begin by seeking insights from the literature on host–parasite interactions, then expand to consider networks of interactions between members of the microbial community. A central aspect of the environment is host nutrition. We describe how interactions between the nutrient environment, the metabolic and behavioral responses of the host and the microbiome can be studied using an integrative framework called nutritional geometry, which integrates and maps multiple aspects of the host and microbial response in multidimensional nutrient intake spaces.

Evolutionary models for the retention of adult–adult social play in primates: The roles of diet and other factors associated with resource acquisition

What factors in animal life history facilitate or reduce the probability that a species will perform play behavior? While some relationships are known within species and across individuals, it is not obvious that such relationships can be used to explain differences and similarities in amount and type of play across large taxonomic groupings of animals, let alone transitions among them. Primates encompass a relatively large assemblage of species that differ in numerous dietary, habitat, reproductive, and physiological processes. While all juvenile primates engage in social play, far fewer primate species engage in social play as adults. Here, derived from theory and more small-scale comparisons, we explore several biological and behavioral phenomena that differ among nonhuman primates and which may explain differences in the occurrence of adult–adult social play. We used phylogenetic logistic regression to assess the correlation of adult play with various life-history, metabolic and socioecological variables. Although the main contribution of our paper is demonstrating use of phylogenetic methods in the context of play evolution, suggestive but not significant evidence was found that adult sexual and nonsexual social play is influenced by diet, habitat, reproductive, and metabolic factors, sometimes in opposite directions, that we discuss along with needed future analyses involving improved data and interactions among traits.

Unexpected consequences of a drier world: evidence that delay in late summer rains biases the population sex ratio of an insect.

The complexity of animal life histories makes it difficult to predict the consequences of climate change on their populations. In this paper, we show, for the first time, that longer summer drought episodes, such as those predicted for the dry Mediterranean region under climate change, may bias insect population sex ratio. Many Mediterranean organisms, like the weevil Curculio elephas, become active again after summer drought. This insect depends on late summer rainfall to soften the soil and allow adult emergence from their underground refuges. We found that, as in many protandric species, more C. elephas females emerged later in the season. Male emergence timing was on average earlier and also more dependent on the beginning of late summer rainfall. When these rains were delayed, the observed weevil sex ratio was biased towards females. So far, the effects of global warming on animal sex ratios has been reported for temperature-dependent sex determination in reptiles. Our results show that rainfall timing can also bias the sex ratio in an insect, and highlight the need for keeping a phenological perspective to predict the consequences of climate change. We must consider not just the magnitude of the predicted changes in temperature and rainfall but also the effects of their timing.

Energy regulation in context: Free-living female arctic ground squirrels modulate the relationship between thyroid hormones and activity among life history stages

Thyroid hormones (THs), key regulators of lipid and carbohydrate metabolism, are likely modulators of energy allocation within and among animal life history stages. Despite their role in modulating metabolism, few studies have investigated whether THs vary among life history stages in free-living animals or if they exhibit stage-specific relationships to total energy expenditure and activity levels. We measured plasma total triiodothyronine (tT3) and thyroxine (tT4) at four, discrete life history stages of female arctic ground squirrels from two different populations in northern Alaska to test whether plasma THs correlate with life history stage-specific changes in metabolic rate and energy demand. We also tested whether THs explained individual variation in aboveground activity levels within life history stages. T3 peaked during lactation and was lowest during pre-hibernation fattening, consistent with known changes in basal metabolism and core body temperature. In contrast, T4 was elevated shortly after terminating hibernation but remained low and stable across other life-history stages in the active season. THs were consistently higher in the population that spent more time above-ground but the relationship between THs and activity varied among life history stages. T3 was positively correlated with activity only during lactation (r2=0.50) whereas T4 was positively correlated with activity immediately following lactation (r2=0.48) and during fattening (r2=0.53). Our results support the hypothesis that THs are an important modulator of basal metabolism but also suggest that the relationship between THs and activity varies among life history stages.

Mercury and cortisol in Western Hudson Bay polar bear hair.

Non-invasive methods of assessing animal health and life history are becoming increasingly popular in wildlife research; hair samples from polar bears (Ursus maritimus), are being used to study an ever broader range of anthropogenic and endocrine compounds. A number of contaminants are known to disrupt endocrine function in polar bears. However, the relationship between mercury and cortisol remains unknown, although mercury is an endocrine disruptor in other species. Here, we examine the relationship between concentrations of cortisol and total mercury (THg) analyzed in guard hair from 378 polar bears (184 females, 194 males) sampled in Western Hudson Bay, 2004-2012. The difference in mean cortisol concentration between female (0.8 ± 0.6 pg/mg) and male (0.7 ± 0.5 pg/mg) polar bears bordered on significance (p = 0.054). However, mean mercury concentration was significantly greater (p = 0.009) in females (4.7 ± 1.4 μg/g) than males (4.3 ± 1.2 μg/g). Hair cortisol in males was significantly influenced by mercury, age, and fatness, as well as interactions between mercury and year, mercury and fatness, and year and fatness (all: p < 0.03) (multiple regression analysis, whole model: r(2) = 0.14, F(7,185) = 4.43, p = 0.0001). Fatness was the only significant variable in the multiple regression analysis for females (r(2) = 0.06, F(1,182) = 13.0, p = 0.0004). In conclusion, a significant, but complex, relationship was found between mercury and cortisol concentrations in hair from male, but not female, polar bears.

Habitat preference facilitates successful early breeding in an open‐cup nesting songbird

Summary Selecting breeding habitats that ameliorate environmental limits on fitness and facilitate successful reproduction should benefit individual animals. This is particularly true in the temperate zone, where breeding early in a season presents a unique series of environmental challenges that can limit an individual's fitness. While many studies document links between habitat quality and reproductive success, few identify the cues used to assess habitat quality or the components of reproduction most influenced by occupying higher quality habitat, particularly during the early breeding season. We used detailed spatial maps and observations of all early season nesting attempts in an insular song sparrow (Melospiza melodia) population over 38 years to estimate the influence of nest‐site preference on reproductive success and to test whether relative microclimate or food availability may act as cues for early season site selection. Female sparrows in preferred early season nest sites had earlier laying dates, exhibited more energetically efficient incubation behaviour and produced more offspring that recruited to the population than those nesting in less‐preferred sites. Preference for potential nesting sites was positively related to leaf damage by Lepidopteran larvae, an indicator of food abundance, negatively related to early season microclimate, likely due to greater vegetation cover, and unrelated to site‐specific plant phenology. Our findings show that breeding in preferred, high‐quality habitat may offer females a fitness advantage by facilitating early laying and the production of offspring more likely to recruit to the population at a lower potential reproductive cost to the parent. We provide a clear demonstration of potential links between habitat preference and quality and their contributions to the ecology and life history of animals in seasonal environments.

How perceived predation risk shapes patterns of aging in water fleas

Predation is an important selection pressure which shapes aging patterns in natural populations, and it is also a significant factor in the life history decisions of individuals. Exposure to the perceived threat of size-dependent fish predation has been shown to trigger adaptive responses in animal life history including an increase in early reproductive output. In water fleas, this response to perceived predation risk appears to have a cost, as a lifespan in an environment free of predation cues is 20% longer. The aim of this study is to establish the biodemographic basis of phenotypic differences in the water flea lifespan which are induced by the cues of fish predation. We examined mortality by fitting the Gompertz–Makeham model of mortality to large cohorts of two cladoceran species, Daphnia longispina and Diaphanosoma brachyurum. Our findings indicate that perceived exposure to the threat of fish predation (induced through chemical cues) only accelerated the rate of aging in Diaphanosoma, and not in Daphnia where the treatment led to an earlier onset of aging. The second of these two phenotypic responses is consistent with the genetically based differences between Daphnia from habitats that differ with respect to predation risk. In contrast, the response of Diaphanosoma demonstrates that the cue of extrinsic mortality—in this case, fish predation—is a key factor in shaping these cladoceran life histories in the wild, and is one of the few interventions which has been shown to induce a plastic change in the rate of aging.

Refinement of welfare through development of a quantitative system for assessment of lifetime experience

AbstractThis paper proposes a system that uses intrinsic study data to provide a clear visualisation of the stresses involved during the animal's life history that can be applied to all types of studies, even those not requiring invasive techniques. Thus, it provides an opportunity for researchers to identify and refine key events which impact on the welfare of an animal, and to explain clearly the totality of any necessary harms when justifying the research. Assessment of animal welfare depends on measurement of a number of parameters which will vary according to species, the animal's environment and the scientific procedure, all of which are inter-related. Currently, there are few tools to assess the effects of lifetime events on welfare or even, in some cases, to recognise that they have an impact on the level of suffering. A matrix to assess the combined effects of environment, experimental and contingent events on welfare has been applied, retrospectively, to programmes of work involving macaques (Macaca mulatta and M. fascicularis). Lifetime records, available for animals from their birth in the breeding colony through to experimental use in vaccine efficacy evaluation studies, were analysed as a robust validation test for the assessment matrix and refinement of the way in which information on these events is captured. A meaningful assessment method is required prospectively for project licence applications and retrospectively for licence review or decisions on re-use. The analysis will provide information that would support the application of refinements that would optimally enhance the lives of experimental animals.

Laying date, incubation and egg breakage as determinants of bacterial load on bird eggshells: experimental evidence.

Exploring factors guiding interactions of bacterial communities with animals has become of primary importance for ecologists and evolutionary biologists during the last years because of their likely central role in the evolution of animal life history traits. We explored the association between laying date and eggshell bacterial load (mesophilic bacteria, Enterobacteriaceae, Staphylococci, and Enterococci) in natural and artificial magpie (Pica pica) nests containing fresh commercial quail (Coturnix coturnix) eggs. We manipulated hygiene conditions by spilling egg contents on magpie and artificial nests and explored experimental effects during the breeding season. Egg breakage is a common outcome of brood parasitism by great spotted cuckoos (Clamator glandarius) on the nests of magpie, one of its main hosts. We found that the treatment increased eggshell bacterial load in artificial nests, but not in magpie nests with incubating females, which suggests that parental activity prevents the proliferation of bacteria on the eggshells in relation to egg breakage. Moreover, laying date was positively related to eggshell bacterial load in active magpie nests, but negatively in artificial nests. The results suggest that variation in parental characteristics of magpies rather than climatic variation during the breeding season explained the detected positive association. Because the eggshell bacterial load is a proxy of hatching success, the detected positive association between eggshell bacterial loads and laying date in natural, but not in artificial nests, suggests that the generalized negative association between laying date and avian breeding success can be, at least partially, explained by differential bacterial effects.

Older female little penguins Eudyptula minor adjust nutrient allocations to both eggs

How individuals allocate resources to reproduction is a fundamental concept in animal life history theory. While it is crucial to quantify the relative allocation of somatic reserves to reproduction by avian females; variation at the individual and intra-clutch level has generally been neglected. We investigated nutrient allocation to eggs of little penguins (Eudyptula minor, Forster, 1781) using automated body-mass recording and natural δ13C and δ15N values for plasma and blood cells of incubating females, and down feathers of their chicks. Further, we evaluated the role of female age (a proxy for experience or senescence) and condition as drivers of individual strategies within this population. Little penguins increased their body masses during a short period prior the onset of reproduction, suggesting that they were accumulating resources to cope with reproductive requirements. Estimated endogenous contribution to eggs was relatively low (~20%), and female age was revealed as a major factor modulating individual variations in resource allocation strategies. Older females accumulated larger amounts of reserves before laying (up to 40% body mass increases) and relied more on endogenous resources (up to 45%) for clutch production than younger females. Our findings suggest that females were able to adjust their endogenous investment between their two chicks, with somatic reserve inputs to heavier siblings showing a bimodal distribution (mean±SD; 16.7±5.9% and 36.5±4.4%) that contrasted with the unimodal distribution observed for lighter siblings (17.8±8.7%). Here, we provide evidence pointing to age and age-related changes as major factors modulating individual decisions on the amount of somatic reserves allocated to eggs. We additionally identified two distinct allocation strategies at the intra-clutch level that may favour siblings with greater chances to fledge, revealing a novel clutch size reduction strategy in seabirds that produce two eggs of similar size but involving a differential nutrient investment in eggs.

Did neurons evolve twice on Earth?

Translucent comb jellies are some of the most primitive animals on Earth, yet they have remarkable nervous systems. Controversial data discussed at a meeting in London last month proposes that their neurons are unlike any others on Earth. This could be evidence that neurons evolved more than once in the history of animal life. The suggestion that neurons evolved in parallel multiple times has divided biologists for over a century. Ultimately, Erich Jarvis of Duke University in North Carolina told a Royal Society conference In March, the question relates to how special they are. If neurons evolved several tunes on the planet, then it becomes more likely that they could evolve elsewhere in the universe.

Adaptive contraction of diet breadth affects sexual maturation and specific nutrient consumption in an extreme generalist omnivore.

Animals balance their intake of specific nutrients, but little is known about how they do so when foraging in an environment with toxic resources and whether toxic foods promote adaptations that affect life history traits. In German cockroach (Blattella germanica) populations, glucose aversion has evolved in response to glucose-containing insecticidal baits. We restricted newly eclosed glucose-averse (GA) and wild-type (WT) female cockroaches to nutritionally defined diets varying in protein-to-carbohydrate (P:C) ratio (3:1, 1:1, or 1:3) or gave them free choice of the 3:1 and 1:3 diets, with either glucose or fructose as the sole carbohydrate source. We measured consumption of each diet over 6days and then dissected the females to measure the length of basal oocytes in their ovaries. Our results showed significantly lower consumption by GA compared to WT cockroaches when restricted to glucose-containing diets, but also lower fructose intake by GA compared to WT cockroaches when restricted to high fructose diets or given choice of fructose-containing diets. Protein intake was regulated tightly regardless of carbohydrate intake, except by GA cockroaches restricted to glucose-containing diets. Oocyte growth was completely suppressed in GA females restricted to glucose-containing diets, but also significantly slower in GA than in WT females restricted to fructose-containing diets. Our findings suggest that GA cockroaches have adapted to reduced diet breadth through endocrine adjustments which reduce requirements for energetic fuels. Our study illustrates how an evolutionary change in the chemosensory system may affect the evolution of other traits that govern animal life histories.

The Dominance of Introduced Plant Species in the Diets of Migratory Galapagos Tortoises Increases with Elevation on a Human‐Occupied Island

AbstractThe distribution of resources and food selection are fundamental to the ecology, life history, physiology, population dynamics, and conservation of animals. Introduced plants are changing foraging dynamics of herbivores in many ecosystems often with unknown consequences. Galapagos tortoises, like many herbivores, undertake migrations along elevation gradients driven by variability in vegetation productivity which take them into upland areas dominated by introduced plants. We sought to characterize diet composition of two species of Galapagos tortoises, focussing on how the role of introduced forage species changes over space and the implications for tortoise conservation. We quantified the distribution of tortoises with elevation using GPS telemetry. Along the elevation gradient, we quantified the abundance of introduced and native plant species, estimated diet composition by recording foods consumed by tortoises, and assessed tortoise physical condition from body weights and blood parameter values. Tortoises ranged between 0 and 429 m in elevation over which they consumed at least 64 plant species from 26 families, 44 percent of which were introduced species. Cover of introduced species and the proportion of introduced species in tortoise diets increased with elevation. Introduced species were positively selected for by tortoises at all elevations. Tortoise physical condition was either consistent or increased with elevation at the least biologically productive season on Galapagos. Santa Cruz tortoises are generalist herbivores that have adapted their feeding behavior to consume many introduced plant species that has likely made a positive contribution to tortoise nutrition. Some transformed habitats that contain an abundance of introduced forage species are compatible with tortoise conservation.

Import and export fluxes of macrozooplankton are taxa- and season-dependent at Jiuduansha marsh, Yangtze River estuary

Macrozooplankton may play important roles in influencing nutrient exchange between salt marsh and nearby estuarine ecosystems through predator-prey interactions and their transport by tidal flows. In this study, macrozooplankton transport through year-round monthly sampling was investigated in a salt marsh creek of the Yangtze River estuary. Twenty-one orders of macrozooplankton were captured. Calanoida and Decapoda were dominant and numerically comprised 59.59% and 37.59% respectively of the total captured macrozooplankton throughout the year. Decapoda mainly occurred in April, May and June. In other months, the Calanoida contributed over 90% of the total individuals. The annual Ferrari index (I) for total individual number of macrozooplankton was 0.27, which generally supports the viewpoint that salt marshes are sources of zooplankton. The salt marsh was mainly a source for decapods and mysids, possibly because of larval release in their breeding seasons. The marsh was also a source for amphipods, probably because some benthic forms became transient planktonic forms during tidal water flushing. Copepods and fish larvae exhibited net import into the salt marsh, which may result from predation from salt marsh settlers or retention in the salt marsh. Monthly Ferrari index (I) estimations revealed that the role of the salt marsh as a sink or source of macrozooplankton was time-dependent, which is related to the life history of animals. This study showed that whether the salt marsh zooplankton act as energy importers or exporters is group/taxa-dependent and time-dependent.

Living the paleofantasy?

Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live, by Marlene Zuk. ISBN 978-0393-08137-4 New York: W. W. Norton & Company, 2013. 328pp. H/b $27.95. My particular interest in this topic is my research focus on the evolution of human diets, and the “paleodiet” fad has made my research relevant recently. I’m always on the lookout for articles and books that communicate about prehistoric diets – and human evolution in general – to the general public. This book does a superb job. In fact, I’ve been asked by several people if and when I might want to write a book, and now I’ve been telling them that the book I’d want to write has already been written; this one! Dr. Marlene Zuk is a Professor in the College of Biological Sciences at the University of Minnesota, studying how natural and sexual selection pressures shape the behavior, life history, and morphology of animals. Specifically, her lab investigates the conflict between natural and sexual selection in Pacific field crickets. While her core research may sound a bit dry, this book is absolutely drenched with witty, lively, accessible information about examples of past and present evolution as they pertain to the modern myth that we have not had time to evolve in response to modern pressures and circumstances. How can you not immediately be hooked by a book whose first sentence is “The first thing you have to do to study 4,000year-old DNA is take off your clothes”? In the introduction, and repeatedly throughout the book, Zuk elegantly breaks down this “paleofantasy” and dispels many myths on which it rests. Some of the main ones include the idea that at some idyllic point in the past, we were “perfectly adapted to our environments” (p. 7), when in fact organisms with seemingly flawless adaptations are actually “full of compromises, jury-rigged like all other organisms” (p. 8) that “we have trade-offs and “good

Tracing historical animal husbandry, meat trade, and food provisioning: A multi-isotopic approach to the analysis of shipwreck faunal remains from the William Salthouse, Port Phillip, Australia

Salted meats were an important foodstuff throughout recent centuries, not only as a protein source during long distance voyages but also in New World colonies. They were often used in conjunction with locally husbanded animals in areas where it was possible to raise European livestock. Isotope analysis can potentially be used to determine the sources and relative contributions of imported vs. local meats. This paper explores the stable carbon, nitrogen, and sulfur isotope values of bone collagen from barreled salt pork and beef products (n=18) recovered from the wrecksite of the William Salthouse, a British ship that sank in 1841 while undertaking the first ever attempt at trade between Canada and Australia. Results show a pronounced heterogeneity in animal life histories and highlight a need for a better understanding of variation in animal husbandry practices in major livestock production centers during the historical period.

Small scale camelid husbandry on the north coast of Peru (Virú Valley): Insight from stable isotope analysis

This study presents carbon and nitrogen isotopic compositions for bone collagen and serially sampled hair from a large collection of South American camelids from two Early Intermediate Period (c. 200 BC to AD 800) sites (Huaca Gallinazo and Huaca Santa Clara) in the Virú Valley (north coast of Peru). The isotopic compositions of these camelids are consistent with plant isotopic compositions from coastal and low altitude settings, but not from high altitude environments, suggesting that at least some of these animals were raised locally. We present several methodological approaches with respect to the treatment of isotopic data from archaeological contexts, outlining quantitative approaches that can provide considerable insight into isotopic variation (within groups, within individuals, between groups, between individuals), as well as temporal variation in isotopic compositions in incrementally growing tissues. We contend that focusing explicitly on variation in animal life histories has the greatest potential with respect to better understanding human–animal interactions in the past. The results demonstrate a large amount of isotopic variability among individuals and an inconsistent amount of within-individual variation, with no consistent shift in the diet leading up to the time of death for a group of animals from a single ritual event. This result suggests that camelid husbandry in the Virú Valley was a small-scale activity, with groups of camelids being managed by families or other small social units. Animals were likely kept primarily in close association to human habitation sites and provided with a diverse array of fodder. These prolonged interactions, occurring at a limited spatial scale, would have allowed a high degree of mutual familiarity to develop between humans and animals. Isotopic compositions for late Middle Horizon (c. AD 1100) sacrificed llamas from Huaca Santa Clara are consistent with Early Intermediate Period camelids, suggesting temporal stability in this small-scale camelid management strategy on the coast, which was fundamentally different from camelid herding in the pastures of the Andean highlands. Isotopic analysis of prehistoric livestock has great potential with respect to better understanding animal husbandry practices and human–animal interactions in the broadest sense because the data provide insight into the ways in which animals lived, rather than the manner in which they died. The variation-centered methodologies outlined in this paper provide a framework with which to approach some of these issues, highlighting the significance of understanding variability in livestock life histories.

Validade da técnica de foto-identificação para analisar marcas naturais em Melanophryniscus montevidensis (Anura: Bufonidae)

Individual identification is useful for answering a variety of biological questions about animal life histories. Most of the techniques used to mark amphibians are invasive and can cause negative effects, compromising individual survivorship and biasing studies. Photo-identification consists in the identification of specimens based on photographic records of unique color-design patterns. This technique has been used with success in several amphibian species. Melanophryniscus montevidensis is an endangered anuran species inhabiting the Uruguayan Atlantic coast. The general pattern of coloration is black with red and yellow blotches on the belly. In this study, we validated the technique of photo-identification assisted by software for individual recognition in M. montevidensis using natural markings. Field trips were performed over 16 months during which, the ventral color pattern of specimens was photographed. The photos were edited and analyzed with the Wild-ID 1.0 software for photographic reconnaissance. An efficiency of 100% was obtained in the visual recognition and 90% in the detection of recaptures using the software. The use of photo-identification using natural marks is an effective technique in this species, because the color pattern of the belly was highly variable among individuals and remained unchanged in individuals over the 16 month period. In this evaluation the use of software for photo-identification was necessary for the treatment of large databases.

The expression of pre- and postcopulatory sexually selected traits reflects levels of dietary stress in guppies.

Environmental and ecological conditions can shape the evolution of life history traits in many animals. Among such factors, food or nutrition availability can play an important evolutionary role in moderating an animal's life history traits, particularly sexually selected traits. Here, we test whether diet quantity and/or composition in the form of omega-3 long chain polyunsaturated fatty acids (here termed ‘n3LC’) influence the expression of pre- and postcopulatory traits in the guppy (Poecilia reticulata), a livebearing poeciliid fish. We assigned males haphazardly to one of two experimental diets supplemented with n3LC, and each of these diet treatments was further divided into two diet ‘quantity’ treatments. Our experimental design therefore explored the main and interacting effects of two factors (n3LC content and diet quantity) on the expression of precopulatory (sexual behaviour and sexual ornamentation, including the size, number and spectral properties of colour spots) and postcopulatory (the velocity, viability, number and length of sperm) sexually selected traits. Our study revealed that diet quantity had significant effects on most of the pre- and postcopulatory traits, while n3LC manipulation had a significant effect on sperm traits and in particular on sperm viability. Our analyses also revealed interacting effects of diet quantity and n3LC levels on courtship displays, and the area of orange and iridescent colour spots in the males’ colour patterns. We also confirmed that our dietary manipulations of n3LC resulted in the differential uptake of n3LC in body and testes tissues in the different n3LC groups. This study reveals the effects of diet quantity and n3LC on behavioural, ornamental and ejaculate traits in P. reticulata and underscores the likely role that diet plays in maintaining the high variability in these condition-dependent sexual traits.