Effects of inbreeding and elevated rearing temperatures on strategic sperm investment.

Males often strategically adjust the number of available sperm based on the social context (i.e. sperm priming response), but it remains unclear how environmental and genetic factors shape this adjustment.

Effects of past mating behavior versus past ejaculation on male mate choice and male attractiveness.

Past reproductive effort allows males to assess their ability to acquire mates, but it also consumes resources that can reduce their future competitive ability. Few studies have examined how a male's reproductive history affects his subsequent mate choice, and, to date, no study has determined the relative contribution of past mating behavior and past ejaculate production because these two forms of investment are naturally highly correlated. Here, we disentangled the relative effects of past mating behavior and past ejaculate production in mosquitofish () by experimentally preventing some males from ejaculating when trying to mate.

Mitochondrial function and sexual selection: can physiology resolve the 'lek paradox'?

Across many taxa, males use elaborate ornaments or complex displays to attract potential mates. Such sexually selected traits are thought to signal important aspects of male 'quality'. Female mating preferences based on sexual traits are thought to have evolved because choosy females gain direct benefits that enhance their lifetime reproductive success (e.

Long-term environmental stability does not erode plasticity in nest building responses to changing ambient conditions.

The primary function of animal nests is to protect developing offspring from hostile and fluctuating environments. Animal builders have been shown to adjust nest construction in response to changes in their environment. However, the extent of this plasticity, and its dependence on an evolutionary history of environmental variability, is not well understood.

An innovative approach to using an intensive field course to build scientific and professional skills.

This paper reports on the design and evaluation of Field Studies in Functional Ecology (FSFE), a two-week intensive residential field course that enables students to master core content in functional ecology alongside skills that facilitate their transition from "student" to "scientist." We provide an overview of the course structure, showing how the constituent elements have been designed and refined over successive iterations of the course. We detail how FSFE students: (1) Work closely with discipline specialists to develop a small group project that tests an hypothesis to answer a genuine scientific question in the field; (2) Learn critical skills of data management and communication; and (3) Analyze, interpret, and present their results in the format of a scientific symposium.

Effects of developmental and adult environments on ageing.

Developmental and adult environments can interact in complex ways to influence the fitness of individuals. Most studies investigating effects of the environment on fitness focus on environments experienced and traits expressed at a single point in an organism's life. However, environments vary with time, so the effects of the environments that organisms experience at different ages may interact to affect how traits change throughout life.

The high invasion success of fall armyworm is related to life-history strategies across a range of stressful temperatures.

Background: Insects living in unfavorably high or low temperatures are predicted to display a fast or slow life-history strategy. Here, we examined life histories of fall armyworm (FAW), a globally important invasive species with a broad ecological niche, at five constant temperatures of 13, 19, 25, 31 and 37°C, to study life-history responses to different temperatures.

Results: In our experiment, FAW had lower lifetime fecundity at unfavorable temperatures, a finding that is consistent with the idea that FAW can shift resources from reproduction to other functions under stressful conditions-such as heat or cold tolerance.

Disentangling the effects of male age and mating history: Contrasting effects of mating history on precopulatory mating behavior and paternity success.

Many studies ask whether young or older males are better at acquiring mates. Even so, how age affects reproductive success is still poorly understood because male age and mating history are confounded in most studies: older males usually have more mating experience. To what extent does mating history rather than age explain variation in male mating success? And how do mating history and male age determine paternity when there is also postcopulatory sexual selection? Here, we experimentally manipulated the mating history of old and young males in the eastern mosquitofish (Gambusia holbrooki).

Male age alone predicts paternity success under sperm competition when effects of age and past mating effort are experimentally separated.

Older males often perform poorly under post-copulatory sexual selection. It is unclear, however, whether reproductive senescence is because of male age itself or the accumulated costs of the higher lifetime mating effort that is usually associated with male age. To date, very few studies have accounted for mating history and sperm storage when testing the effect of male age on sperm traits, and none test how age and past mating history influence paternity success under sperm competition.

The role of maternal effects on offspring performance in familiar and novel environments.

Maternal effects are an important evolutionary force that may either facilitate adaptation to a new environment or buffer against unfavourable conditions. The degree of variation in traits expressed by siblings from different mothers is often sensitive to environmental conditions. This could generate a Maternal-by-Environment interaction (M × E) that inflates estimates of Genotype-by-Environment effects (G × E).

Combined effects of rearing and testing temperatures on sperm traits.

Temperature experienced during early development can affect a range of adult life-history traits. Animals often show seemingly adaptive developmental plasticity-with animals reared at certain temperatures performing better as adults at those temperatures. The extent to which this type of adaptive response occurs in gonadal tissue that affects sperm traits is, however, poorly studied.

Stress in the city: meta-analysis indicates no overall evidence for stress in urban vertebrates.

As cities continue to grow it is increasingly important to understand the long-term responses of wildlife to urban environments. There have been increased efforts to determine whether urbanization imposes chronic stress on wild animals, but empirical evidence is mixed. Here, we conduct a meta-analysis to test whether there is, on average, a detrimental effect of urbanization based on baseline and stress-induced glucocorticoid levels of wild vertebrates.

The effects of competition on fitness depend on the sex of both competitors.

In intraspecific competition, the sex of competing individuals is likely to be important in determining the outcome of competitive interactions and the way exposure to conspecifics during development influences adult fitness traits. Previous studies have explored differences between males and females in their response to intraspecific competition. However, few have tested how the sex of the competitors, or any interactions between focal and competitor sex, influences the nature and intensity of competition.

Shifts in Reproductive Investment in Response to Competitors Lower Male Reproductive Success.

AbstractIn many species, males exhibit phenotypic plasticity in sexually selected traits when exposed to social cues about the intensity of sexual competition. To date, however, few studies have tested how this plasticity affects male reproductive success. We initially tested whether male mosquitofish, (Poeciliidae), change their investment in traits under pre- and postcopulatory sexual selection depending on the social environment.

Breaking barriers? Ethnicity and socioeconomic background impact on early career progression in the fields of ecology and evolution.

The academic disciplines of Science, Technology, Engineering and Mathematics (STEM) have long suffered from a lack of diversity. While in recent years there has been some progress in addressing the underrepresentation of women in STEM subjects, other characteristics that have the potential to impact on equality of opportunity have received less attention. In this study, we surveyed 188 early career scientists (ECRs), defined as within 10 years of completing their PhD, in the fields of ecology, evolutionary biology, behaviour, and related disciplines.

No link between nymph and adult coloration in shield bugs: weak selection by predators.

Many organisms use different antipredator strategies throughout their life, but little is known about the reasons or implications of such changes. For years, it has been suggested that selection by predators should favour uniformity in local warning signals. If this is the case, we would expect high resemblance in colour across life stages in aposematic animals where young and adults share similar morphology and habitat.

Sex in the city: sexual selection and urban colonization in passerines.

Urbanization leads to a rapid and drastic transformation of habitats, forcing native fauna to manage novel ecological challenges or to move. Sexual selection is a powerful evolutionary force, which is sometimes predicted to enhance the ability of species to adapt to novel environments because it allows females to choose high-quality males, but other times is predicted to reduce the viability of populations because it pushes males beyond naturally selected optima. However, we do not know whether or how sexual selection contributes to the likelihood that animals will establish in urban areas.

An experimental test for body size-dependent effects of male harassment and an elevated copulation rate on female lifetime fecundity and offspring performance.

Many studies investigate the benefits of polyandry, but repeated interactions with males can lower female reproductive success. Interacting with males might even decrease offspring performance if it reduces a female's ability to transfer maternal resources. Male presence can be detrimental for females in two ways: by forcing females to mate at a higher rate and through costs associated with resisting male mating attempts.

Evidence that nonsignificant results are sometimes preferred: Reverse P-hacking or selective reporting?

There is increased concern about poor scientific practices arising from an excessive focus on P-values. Two particularly worrisome practices are selective reporting of significant results and 'P-hacking'. The latter is the manipulation of data collection, usage, or analyses to obtain statistically significant outcomes.

Good parenting may not increase reproductive success under environmental extremes.

For species exhibiting parental care, the way in which parents adjust care behaviour to compensate for environmental change potentially influences offspring survival and, ultimately, population viability. Using the three-spined stickleback (Gasterosteus aculeatus) - a species in which males provide parental care by building and tending a nest and fanning the eggs - we examined how low dissolved oxygen (DO) levels affect paternal care, embryo development and survival. Although levels of nest tending were unaffected by DO level, we found that larger males fanned their embryos more under low oxygen conditions.

Transgenerational effects of maternal sexual interactions in seed beetles.

Mating often bears large costs to females, especially in species with high levels of sexual conflict over mating rates. Given the direct costs to females associated with multiple mating, which include reductions in lifespan and lifetime reproductive success, past research focused on identifying potential indirect benefits (through increases in offspring fitness) that females may accrue. Far less attention has, however, been devoted to understanding how costs of sexual interactions to females may extend across generations.

What happens to offspring when parents are inbred, old or had a poor start in life? Evidence for sex-specific parental effects.

Parental effects on offspring performance have been attributed to many factors such as parental age, size and condition. However, we know little about how these different parental characteristics interact to determine parental effects, or the extent to which their effect on offspring depends on either the sex of the parent or that of the offspring. Here we experimentally tested for effects of variation in parents' early diet and inbreeding levels, as well as effects of parental age, and for potential interactive effects of these three factors on key aspects of offspring development in the mosquitofish (Gambusia holbrooki).

Does the winner-loser effect determine male mating success?

Winning or losing a fight can have lasting effects on competitors. Controlling for inherent fighting ability and other factors, a history of winning often makes individuals more likely to win future contests, while the opposite is true for losers (the 'winner-loser effect'). But does the winner-loser effect also influence a male's mating success? We experimentally staged contests between male mosquitofish () such that focal males either won or lost three successive encounters with stimulus males.

Increased temperature disrupts chemical communication in some species but not others: The importance of local adaptation and distribution.

Environmental conditions experienced by a species during its evolutionary history may shape the signals it uses for communication. Consequently, rapid environmental changes may lead to less effective signals, which interfere with communication between individuals, altering life history traits such as predator detection and mate searching. Increased temperature can reduce the efficacy of scent marks released by male lizards, but the extent to which this negative effect is related to specific biological traits and evolutionary histories across species and populations have not been explored.

Maternal-by-environment but not genotype-by-environment interactions in a fish without parental care.

The impact of environmental conditions on the expression of genetic variance and on maternal effects variance remains an important question in evolutionary quantitative genetics. We investigate here the effects of early environment on variation in seven adult life history, morphological, and secondary sexual traits (including sperm characteristics) in a viviparous poeciliid fish, the mosquitofish Gambusia holbrooki. Specifically, we manipulated food availability during early development and then assessed additive genetic and maternal effects contributions to the overall phenotypic variance in adults.