Artificial light at night alters life history in a nocturnal orb-web spider

The prevalence of artificial light at night (ALAN) is increasing rapidly around the world. The potential physiological costs of this night lighting are often evident in life history shifts. We investigated the effects of chronic night-time exposure to ecologically relevant levels of LED lighting on the life history traits of the nocturnal Australian garden orb-web spider (Eriophora biapicata). We reared spiders under a 12-h day and either a 12-h natural darkness (∼0 lux) or a 12-h dim light (∼20 lux) night and assessed juvenile development, growth and mortality, and adult reproductive success and survival. We found that exposure to ALAN accelerated juvenile development, resulting in spiders progressing through fewer moults, and maturing earlier and at a smaller size. There was a significant increase in daily juvenile mortality for spiders reared under 20 lux, but the earlier maturation resulted in a comparable number of 0 lux and 20 lux spiders reaching maturity. Exposure to ALAN also considerably reduced the number of eggs produced by females, and this was largely associated with ALAN-induced reductions in body size. Despite previous observations of increased fitness for some orb-web spiders in urban areas and near night lighting, it appears that exposure to artificial night lighting may lead to considerable developmental costs. Future research will need to consider the detrimental effects of ALAN combined with foraging benefits when studying nocturnal insectivores that forage around artificial lights

A preliminary molecular phylogeny of shield-bearer moths (Lepidoptera: Adeloidea: Heliozelidae) highlights rich undescribed diversity

Heliozelidae are a widespread, evolutionarily early diverging family of small, day-flying monotrysian moths, for which a comprehensive phylogeny is lacking. We generated the first molecular phylogeny of the family using DNA sequences of two mitochondrial genes (COI and COII) and two nuclear genes (H3 and 28S) from 130 Heliozelidae specimens, including eight of the twelve known genera: Antispila, Antispilina, Coptodisca, Heliozela, Holocacista, Hoplophanes, Pseliastis, and Tyriozela. Our results provide strong support for five major Heliozelidae clades: (i) a large widespread clade containing the leaf-mining genera Antispilina, Coptodisca and Holocacista and some species of Antispila, (ii) a clade containing most of the described Antispila, (iii) a clade containing the leaf-mining genus Heliozela and the monotypic genus Tyriozela, (iv) an Australian clade containing Pseliastis and (v) an Australian clade containing Hoplophanes. Each clade includes several new species and potentially new genera. Collectively, our data uncover a rich and undescribed diversity that appears to be especially prevalent in Australia. Our work highlights the need for a major taxonomic revision of the family and for generating a robust molecular phylogeny using multi-gene approaches in order to resolve the relationships among clades

The Evolution of Functionally Redundant Species; Evidence from Beetles

While species fulfill many different roles in ecosystems, it has been suggested that numerous species might actually share the same function in a near neutral way. So-far, however, it is unclear whether such functional redundancy really exists. We scrutinize this question using extensive data on the world’s 4168 species of diving beetles. We show that across the globe these animals have evolved towards a small number of regularly-spaced body sizes, and that locally co-existing species are either very similar in size or differ by at least 35%. Surprisingly, intermediate size differences (10–20%) are rare. As body-size strongly reflects functional aspects such as the food that these generalist predators can eat, these beetles thus form relatively distinct groups of functional look-a-likes. The striking global regularity of these patterns support the idea that a self-organizing process drives such species-rich groups to self-organize evolutionary into clusters where functional redundancy ensures resilience through an insurance effect

Should Attractive Males Sneak: The Trade-Off between Current and Future Offspring

Peer reviewe

A role for pheromones inmate choice in a lekking sandfly

There is increasing evidence to suggest that pheromone-mediated communication may play an important role in mate choice in many insects. We investigated the possible role of pheromones in mate choice in the lekking sandfly, Lutzomyia longipalpis, and explored whether males or females display any behavioural traits that predict patterns of male mating success. Pairs of virgin males were introduced into a small mating chamber and allowed to interact for approximately 10 min prior to the introduction of a single virgin female. The trial continued until the female copulated with one of the males. We recorded trials on video for later analysis. After a successful copulation, we determined the quantity of pheromone remaining in the glands of both males anti measured the size of the pheromone glands and tergites. We corrected behaviours and measurements for body size (tergite width). Mated males had significantly more pheromone present in their glands after a trial than unmated males. Males differed in how much time they invested in wing fanning. Members of each pair of males spent similar amounts of time wing fanning but mated males and males with more residual pheromone spent more time wing fanning than their counterparts throughout the trial. The time spent wing fanning and the amount of residual pheromone were not correlated, however. A male's ability to win fights did not relate to his reproductive success. Finally, a female was equally likely to wing-fan directly at, or walk away from, either male in a given pair. The possible relationships between the amount of pheromone released and the residual pheromones left in the glands, and the level of male wing fanning and pheromone productivity, are discussed

Sex-role reversed nuptial feeding reduces male kleptoparasitism of females in Zeus bugs (Heteroptera; Veliidae)

Males of a variety of taxa occasionally steal food secured by their mates. In some spiders and insects, males rely entirely on this form of intraspecific kleptoparasitism for their subsistence. However, this male strategy may be costly for females and a variety of different female counteradaptations have been proposed. In Zeus bugs (Phoreticovelia spp.), males ride on the back of their mates for extended periods and females produce a gland secretion that males feed on. By experimentally occluding the dorsal glands in females and varying food availability, we show that nuptial feeding by females reduces the extent to which the males kleptoparasitize their mates. We suggest that females have, at least in part, evolved this unique form of nuptial feeding as a counteradaptation to reduce the rate of kleptoparasitism by males

Age-related sperm transfer and sperm competitive ability in the male hide beetle

The influence of male age on reproductive success after a single mating has been explored widely; however, few studies have investigated whether quantitative or qualitative differences in male sperm are responsible for the observed patterns. Moreover, the role of male age on sperm competitive ability has been largely ignored. We examined the importance of male age on the probability and amount of sperm transferred during a single mating and explored whether sperm competitive ability varies with male age in the hide beetle Dermestes maculatus, a species where sperm viability does not vary with male age. We also investigated whether sperm transfer rates varied with female age. We found that the probability of sperm transfer and the amount of sperm transferred varied with male, but not female, age. All males performed behaviorally successful copulations, but intermediate-age and old males were more likely to transfer sperm successfully and also transferred a greater quantity of sperm than young males. Old males were less likely to transfer sperm than intermediate-age males, but if they did transfer sperm successfully, they transferred comparable amounts. Sperm competitive ability varied with male age and reflected the quantity of sperm transferred. On average, intermediate-age males achieved greater fertilization success when competing against young or old males than when competing against other intermediate-age males. Old males were poor competitors against intermediate-age males, but they achieved significantly higher rates of fertilization when competing against young males. Our findings suggest that quantitative differences in the amount of sperm transferred determine male success in sperm competition in the hide beetle. Copyright 2007.female age; male age; sperm competition; sperm transfer

Gender differences in conference presentations: a consequence of self-selection?

Women continue to be under-represented in the sciences, with their representation declining at each progressive academic level. These differences persist despite long-running policies to ameliorate gender inequity. We compared gender differences in exposure and visibility at an evolutionary biology conference for attendees at two different academic levels: student and post-PhD academic. Despite there being almost exactly a 1:1 ratio of women and men attending the conference, we found that when considering only those who presented talks, women spoke for far less time than men of an equivalent academic level: on average student women presented for 23% less time than student men, and academic women presented for 17% less time than academic men. We conducted more detailed analyses to tease apart whether this gender difference was caused by decisions made by the attendees or through bias in evaluation of the abstracts. At both academic levels, women and men were equally likely to request a presentation. However, women were more likely than men to prefer a short talk, regardless of academic level. We discuss potential underlying reasons for this gender bias, and provide recommendations to avoid similar gender biases at future conferences