A tangerine-scented social odour in a monogamous seabird

Social odours, conspecific chemical signals, have been demonstrated in every class of vertebrate except birds. The apparent absence is surprising, as every bird examined has a functional olfactory system and many produce odours. The crested auklet (Aethia cristatella), a monogamous seabird, exhibits a distinctive tangerine-like scent closely associated with courtship. Using T-maze experiments, we tested […]

Experiments on colour ornaments and mate choice in king penguins

Research on animal ornaments used in mate choice has largely focused on males, particularly for bird species with sexually dimorphic coloured patches of feathers and integument. Relatively less information is available for coloured ornaments of sexually monomorphic species and the use of these ornaments during mate choice. The king penguin, Aptenodytes patagonicus, is a monogamous […]

Female mating preferences, lighting environment, and a test of the sensory bias hypothesis in the bluefin killifish

Sensory drive proposes that environmental conditions affect signalling dynamics and the evolution of signals and receivers. For visual systems, delineating the effects of lighting on mating preferences is difficult because lighting conditions can affect preferences via three mechanisms: (1) genetic differentiation in mating preferences can result from selection under different lighting conditions, (2) development under […]

Sociosexual behavior, male mating tactics, and the reproductive cycle of giraffe Giraffa camelopardalis

Female distribution exerts a major impact on male mating tactics. Giraffe cows have a reproductive cycle, and a social system, that should favor a male roaming reproductive tactic. We conducted a 2-year study of female Rothschild’s giraffe (G. c. rothschildi) reproductive endocrinology in order to characterize attributes of the reproductive cycle and investigate how female […]

Sexual selection is not the origin of long necks in giraffes

The evolutionary origin of the long neck of giraffes is enigmatic. One theory (the ‘sexual selection’ theory) is that their shape evolved because males use their necks and heads to achieve sexual dominance. Support for this theory would be that males invest more in neck and head growth than do females. We have investigated this […]

Comparing entire colour patterns as birds see them

Colour patterns and their visual backgrounds consist of a mosaic of patches that vary in colour, brightness, size, shape and position. Most studies of crypsis, aposematism, sexual selection, or other forms of signalling concentrate on one or two patch classes (colours), either ignoring the rest of the colour pattern, or analysing the patches separately. We […]

Blue tits are ultraviolet tits

The blue tit (Parus caeruleus) has been classified as sexually monochromatic. This classification is based on human colour perception yet, unlike humans, most birds have four spectrally distinct classes of cone and are visually sensitive to wavelengths in the near-ultraviolet (300 to 400 nm). Reflectance spectrophotometry reveals that blue tit plumage shows considerable reflection of […]

Ultraviolet signals in birds are special

Recent behavioural experiments have shown that birds use ultraviolet (UV)-reflective and fluorescent plumage as cues in mate choice. It remains controversial, however, whether such UV signals play a special role in sexual communication, or whether they are part of general plumage coloration. We use a comparative approach to test for a general association between sexual […]

Stress hormones and mate choice

A few recent studies have suggested that glucocorticoid stress hormones can play a role in sexual selection. In terms of mate choice, these studies have shown that individuals can exhibit preferences for mates with either low baseline or peak glucocorticoid levels. This appears to occur because stress hormones can be key mediators of many condition-dependent, […]

Pairs of zebra finches with similar ‘personalities’ make better parents

Although behavioural plasticity should be an advantage in a varying world, there is increasing evidence for widespread stable individual differences in the behaviour of animals: that is, [`]personality’. Here we provide evidence suggesting that sexual selection is an important factor in the evolution of personality in species with biparental care. We carried out a cross-fostering […]