Reproductive Foragers: Male Spiders Choose Mates by Selecting among Competitive Environments

Mate choice frequently operates differently for males and females as a consequence of male competition for mates. Competitive interactions can alter the fitness payoffs of choice and the realization of preferences under natural conditions, yet the majority of male choice studies still use binary trials that ignore social factors. Here we test the importance of contest dynamics in male choice using a framework in which females are considered analogous to foraging patches that are subject to competition. We track the mate choices and interactions of 640 spiders (Nephila plumipes) before and after manipulation of competition within enclosures, modeling the expected fitness payoffs of each male's actual choices and comparing these with all alternative choices. Many males choose new mates once social conditions change and achieve higher fitness than predicted under random movement. Males do not simply move to larger females but choose favorable competitive environments that balance competition and female fecundity, thereby increasing their fitness payoffs. Further, we show for the first time that prior-residence effects, which are known to influence male contests, also have a strong influence in male reproductive contests and can shape male mate choice. These results highlight the importance of situating male choice studies in the relevant social context, as intrasexual interactions can have profound effects on the realization and payoffs of male mate-choice strategies

Data from: Recent social history alters male courtship preferences

Phenotypically plastic mating behaviour may allow males to modify their reproductive behaviour to suit the prevailing social conditions, but we do not know if males only react to immediate social stimuli or change their inherent mate preferences according to their social history. Here we examine the effect of social experiences on the subsequent reproductive behaviour of male guppies under standard conditions, allowing us to distinguish the effect of past and immediate social conditions. Males experienced experimental conditioning periods during which they interacted with three females, either of variable size or of similar size. Females arrived either simultaneously or consecutively. In subsequent standard assays, only males that had experienced females of variable size preferentially courted large females. Further, males exposed to sequential female arrival courted subsequent females more vigorously than males that had experienced simultaneous female arrival. In contrast, males did not alter their coercive mating attempts in relation to their recent social history. These results demonstrate that males use past experiences to modify their subsequent reproductive behaviour rather than reacting only to immediate stimuli, and reveal the sophisticated ways in which males alter their reproductive tactics to suit the social environment and maximise fitness across changing selective landscapes

The use of multiple sources of social information in contest behaviour: testing the social cognitive abilities of a cichlid fish

Theory suggests that living in large social groups with dynamic social interactions often favours the evolution of enhanced cognitive abilities. Studies of how animals assess their own contest ability commonly focus on a single cognitive task, and little is known about the diversity or co-occurrence of cognitive abilities in social species. We examined how a highly social cichlid fish Julidochromis transcriptus uses four major cognitive abilities in contest situations; direct experience, winner/loser effects, social eavesdropping and transitive inference (TI). We conducted experiments in which fish assessed the social status of rivals after either direct physical contests or observed contests. Individuals used direct information from a previous physical encounter to re-establish dominance without additional contact, but winner/loser effects were not observed. Social eavesdropping alone was ruled out, but we found that transitive reasoning was used to infer social dominance of other individuals of unknown status. Our results suggest that in stable hierarchical social groups, estimations of contest ability, based on individual recognition pathways such as TI and direct experience, are more prevalent than social eavesdropping or winner/loser effects. We suggest that advanced cognitive abilities might be widespread among highly social fishes, but have previously gone undetected

Jordan et al Am Nat 2013 data

Coordinate data for all males and females at time 1 and time 2, along with measurements of weight, length, and death

Data from: Reproductive foragers: spider males choose mates by selecting among available competitive environments

Mate choice frequently operates differently for males and females as a consequence of male competition for mates. Competitive interactions can alter the fitness payoffs of choice and the realisation of preferences under natural conditions, yet the majority of male choice studies still use binary trials that ignore social factors. Here we test the importance of contest dynamics in male choice with a large scale experiment, using a framework where females are considered analogous to foraging patches that are subject to competition. We track the mate choices and interactions of 640 spiders (Nephila plumipes) before and after manipulation of competition within enclosures, modelling the expected fitness payoffs of each male's actual choices and comparing these with all alternative choices available. We find that many males choose new females once social conditions change, and achieve higher fitness than predicted under random movement. Males increase their fitness not by moving to larger females but by choosing favourable competitive environments that balance competition and female fecundity. Further, we show for the first time that prior residence effects have a strong influence in male reproductive contests and can shape male mate choice. These results highlight the importance of situating male choice studies in the relevant social context, as intrasexual interactions can have profound effects on the realisation and payoffs of male mate choice strategies

Dryad Evo 11-0373

Excel spreadsheet of observational data imported from JWatcher. Separate tabs for 'consensual' and 'coercive' mating attempts

Social environment and the evolution of male reproductive strategy

Reproduction is by its very nature a social interaction, and should therefore be considered in a social context. By altering the interactions between individuals, social conditions can modify the costs and benefits of reproductive strategies, and hence the evolution of mating behaviour generally. The effect of the social environment is particularly pertinent to studies of male reproductive behaviour due to the competitive nature of male sexual effort. Males must balance the costs of courtship, risk of competition, likelihood of mating, and abundance of alternative mates when considering where and how to invest their reproductive effort. All these factors are shaped by the social environment, which ultimately changes the selective landscape in which male reproductive strategies operate.Here I examine the interaction between the social environment and reproductive strategies using both empirical studies of fish and theoretical modelling approaches. I show that courtship of male guppies, Poecilia reticulata, changes as a function of their social environment, ultimately modifying the costs of lifelong sexual effort. I then use mathematical modelling to predict how different male reproductive strategies will perform as social conditions change, demonstrating that the success of reproductive strategies depends on the abundance of mates and the reproductive strategies used by competing males. I go on to test these predictions empirically, showing that exposing male guppies to social environments differing in female abundance and variance of female quality affects male reproductive strategies employed in subsequent mate encounters.I also examine how animals choose among social groups that offer different reproductive opportunities using two species of social fish, Neolamprologus pulcher and Dascyllus aruanus. I show that reproductive opportunities may be outweighed by survival benefits when animals choose among social groups, and that the reaction of existing group residents can strongly affect the realisation of an individualʼs group membership preferences.Combined, the results of this thesis demonstrate the strong influence of social conditions on a broad range of reproductive behaviours, highlighting the need to examine the evolution of reproductive behaviour in the context of the social environment

Inheritance of traits associated with reproductive potential in Apis mellifera capensis and Apis mellifera scutellata workers

When workers of the thelytokous Cape honeybee, Apis mellifera capensis, come into contact with colonies of the neighboring arrhenotokous subspecies Apis mellifera scutellata, they can become lethal social parasites. We examined the inheritance of 3 traits (number of ovarioles, number of basitarsal hairs, and size of spermatheca) that are thought to be associated with reproductive potential in A. m. capensis workers. To do so, we produced hybrid A. m. scutellata/A. m. capensis queens and backcrossed them to either A. m. capensis or A. m. scutellata drones. We then measured the 3 traits in parental, hybrid, and backcross offspring. We show that the 3 traits are phenotypically correlated. We also show that the expression of ovariole number, basitarsal hairs, and size of spermatheca is influenced by the genotype of the individual and the rearing environment but that the influence of the rearing environment is less important to the number of ovarioles. We hypothesize a single recessive allele (l), present at high frequency in natural A. m. capensis populations, which when homozygous causes larvae to elicit more food. This increased feeding as larvae causes resulting adult workers to develop more queen-like morphology and increased reproductive potential. The number of ovarioles, in contrast, appears to be under independent genetic control.publishe

Data from: The social and ecological costs of an ‘over-extended’ phenotype

Extended phenotypes offer a unique opportunity to experimentally manipulate and identify sources of selection acting on traits under natural conditions. The social cichlid fish Neolamprologus multifasciatus builds nests by digging up aquatic snail shells, creating an extended sexual phenotype that is highly amenable to experimental manipulation through addition of extra shells. Here, we find sources of both positive sexual selection and opposing natural selection acting on this trait; augmenting shell nests increases access to mates, but also increases social aggression and predation risk. Increasing the attractiveness of one male also changed social interactions throughout the social network and altered the entire community structure. Manipulated males produced and received more displays from neighbouring females, who also joined augmented male territories at higher rates than unmanipulated groups. However, males in more attractive territories received more aggression from neighbouring males, potentially as a form of social policing. We also detected a significant ecological cost of the ‘over-extended' phenotype; heterospecific predators usurped augmented nests at higher rates, using them as breeding sites and displacing residents. Using these natural experiments, we find that both social and ecological interactions generate clear sources of selection mediating the expression of an extended phenotype in the wild