Biology Letters

http://rsbl.royalsocietypublishing.org

List of Papers (Total 1,920)

Do Heliconius butterfly species exchange mimicry alleles?

Hybridization has the potential to transfer beneficial alleles across species boundaries, and there are a growing number of examples in which this has apparently occurred. Recent studies suggest that Heliconius butterflies have transferred wing pattern mimicry alleles between species via hybridization, but ancestral polymorphism could also produce a signature of shared ancestry ...

Canadian fishery closures provide a large-scale test of the impact of gillnet bycatch on seabird populations

In 1992, the eastern Canadian gillnet fisheries for northern cod and Atlantic salmon were largely closed. These large-scale fishery closures resulted in the removal of tens of thousands of gillnets known to inflict high levels of seabird mortality. We used this unprecedented opportunity to test the effects of gillnet removal on seabird populations. Consistent with predictions, we ...

Shedding light on moths: shorter wavelengths attract noctuids more than geometrids

With moth declines reported across Europe, and parallel changes in the amount and spectra of street lighting, it is important to understand exactly how artificial lights affect moth populations. We therefore compared the relative attractiveness of shorter wavelength (SW) and longer wavelength (LW) lighting to macromoths. SW light attracted significantly more individuals and species ...

First direct measurements of behavioural responses by Cuvier's beaked whales to mid-frequency active sonar

Most marine mammal­ strandings coincident with naval sonar exercises have involved Cuvier's beaked whales (Ziphius cavirostris). We recorded animal movement and acoustic data on two tagged Ziphius and obtained the first direct measurements of behavioural responses of this species to mid-frequency active (MFA) sonar signals. Each recording included a 30-min playback (one 1.6-s ...

Constraints on muscle performance provide a novel explanation for the scaling of posture in terrestrial animals

Larger terrestrial animals tend to support their weight with more upright limbs. This makes structural sense, reducing the loading on muscles and bones, which is disproportionately challenging in larger animals. However, it does not account for why smaller animals are more crouched; instead, they could enjoy relatively more slender supporting structures or higher safety factors. ...

Collision-based mechanics of bipedal hopping

The muscle work required to sustain steady-speed locomotion depends largely upon the mechanical energy needed to redirect the centre of mass and the degree to which this energy can be stored and returned elastically. Previous studies have found that large bipedal hoppers can elastically store and return a large fraction of the energy required to hop, whereas small bipedal hoppers ...

Memory decay and susceptibility to amnesia dissociate punishment- from relief-learning

Painful events shape future behaviour in two ways: stimuli associated with pain onset subsequently support learned avoidance (i.e. punishment-learning) because they signal future, upcoming pain. Stimuli associated with pain offset in turn signal relief and later on support learned approach (i.e. relief-learning). The relative strengths of such punishment- and relief-learning can be ...

Potential trade-off between vocal ornamentation and spatial ability in a songbird

Bird song is hypothesized to be a reliable indicator of cognition because it depends on brain structure and function. Song features have been found to correlate positively with measures of cognition, but the relationship between song and cognition is complicated because not all cognitive abilities are themselves positively correlated. If cognition is not a unitary trait, ...

Subjective and objective components of resource value additively increase aggression in parasitoid contests

Two major categories of factors are predicted to influence behaviour in dyadic contests; differences in the abilities of the contestants to acquire and retain resources (resource holding potential), and the value of the contested resource (resource value, RV; which comprises objective and subjective components). Recent studies indicate that subjective components affect contest ...

Facial attractiveness is related to women's cortisol and body fat, but not with immune responsiveness

Recent studies suggest that facial attractiveness indicates immune responsiveness in men and that this relationship is moderated by stress hormones which interact with testosterone levels. However, studies testing whether facial attractiveness in women signals their immune responsiveness are lacking. Here, we photographed young Latvian women, vaccinated them against hepatitis B and ...

Spatial learning affects thread tension control in orb-web spiders

Although it is well known that spatial learning can be important in the biology of predators that actively move around in search for food, comparatively little is known about ways in which spatial learning might function in the strategies of sit-and-wait predators. In this study, Cyclosa octotuberculata, an orb-web spider that uses its legs to contract radial threads of its web to ...

Spermatophore consumption in a cephalopod

An individual's gametes can represent a nourishing food source for a manipulative mate. Here, we provide evidence of ejaculate and sperm consumption in a cephalopod. Through labelling male spermatophores with 14C radiolabel, we found that female squid, Sepiadarium austrinum, consumed the spermatophores of their partners and directed the nutrients received into both somatic ...

Horizontal transmission of the father's song in the zebra finch (Taeniopygia guttata)

As is the case for human speech, birdsong is transmitted across generations by imitative learning. Although transfer of song patterns from adults to juveniles typically occurs via vertical or oblique transmission, there is also evidence of horizontal transmission between juveniles of the same generation. Here, we show that a young male zebra finch (Taeniopygia guttata) that has ...

Turtle embryos move to optimal thermal environments within the egg

A recent study demonstrated that the embryos of soft-shelled turtles can reposition themselves within their eggs to exploit locally warm conditions. In this paper, we ask whether turtle embryos actively seek out optimal thermal environments for their development, as do post-hatching individuals. Specifically, (i) do reptile embryos move away from dangerously high temperatures as ...

Plasticity of parental care under the risk of predation: how much should parents reduce care?

Predation can be an important agent of natural selection shaping parental care behaviours, and can also favour behavioural plasticity. Parent birds often decrease the rate that they visit the nest to provision offspring when perceived risk is high. Yet, the plasticity of such responses may differ among species as a function of either their relative risk of predation, or the mean ...

Social learning of a brood parasite by its host

Arms races between brood parasites and their hosts provide model systems for studying the evolutionary repercussions of species interactions. However, how naive hosts identify brood parasites as enemies remains poorly understood, despite its ecological and evolutionary significance. Here, we investigate whether young, cuckoo-naive superb fairy-wrens, Malurus cyaneus, can learn to ...

Spontaneous male death and monogyny in the dark fishing spider

Monogyny (male monogamy) is found in a diverse assemblage of taxa, and recent theoretical work reveals that a male-biased sex ratio can favour the evolution of this relatively rare mating system. We integrate this theoretical framework with field observations and laboratory experiments involving the sexually size dimorphic fishing spider, Dolomedes tenebrosus, to test the ...

Energetic cost of learning and memory can cause cognitive impairment in honeybees

The energetic cost of cognitive functions can lead to either impairments in learning and memory, or to trade-offs with other functions, when the amount of available energy is limited. However, it has been suggested that, under such conditions, social groups such as honeybees might be able to ward off cognitive impairments in individual bees by adjusting resource allocation at the ...

Coping with the cold: predictors of survival in wild Barbary macaques, Macaca sylvanus

We report the death of 30 wild Barbary macaques, living in two groups, during an exceptionally cold and snowy winter in the Middle Atlas Mountains, Morocco. We examined whether an individual's time spent feeding, the quality and number of its social relationships, sex and rank predicted whether it survived the winter or not. The time an individual spent feeding and the number of ...

Hawkmoths produce anti-bat ultrasound

Bats and moths have been engaged in aerial warfare for nearly 65 Myr. This arms race has produced a suite of counter-adaptations in moths, including bat-detecting ears. One set of defensive strategies involves the active production of sound; tiger moths' ultrasonic replies to bat attack have been shown to startle bats, warn the predators of bad taste and jam their biosonar. Here, ...

Playing to an audience: the social environment influences aggression and victory displays

Animal behaviour studies have begun to incorporate the influence of the social environment, providing new opportunities for studying signal strategies and evolution. We examined how the presence and sex of an audience influenced aggression and victory display behaviour in field-captured and laboratory-reared field crickets (Gryllus veletis). Audience type, rearing environment and ...

Stable isotope canopy effects for sympatric monkeys at Taï Forest, Côte d'Ivoire

This study tests the hypothesis that vertical habitat preferences of different monkey species inhabiting closed canopy rainforest are reflected in oxygen isotopes. We sampled bone from seven sympatric cercopithecid species in the Taï forest, Côte d'Ivoire, where long-term study has established taxon-specific patterns of habitat use and diet. Modern rib samples (n = 34) were ...

Surfing in tortoises? Empirical signs of genetic structuring owing to range expansion

Much of our current knowledge about the genetic dynamics in range expansions originates from models, simulations and microcosm experiments that need to be corroborated by field data. Here, we report a neutral genetic pattern that matches the predictions of the genetic surfing theory. Genetic surfing occurs when repeated founding events and genetic drift act on the wave of advance ...