Female Japanese quail affiliate with live males that they have seen mate on video

A female Japanese quail, Coturnix japonica, will increase her tendency to affiliate and mate with a conspecific male after seeing him court and mate with another female. In the present study, we found that female quail increased the time they spent near a live target male after seeing that same male court and mate with another female in a 5-min video displayed on an active-matrix TFT monitor. However, female quail that were shown 5-min video sequences of either a target male standing alone or a randomly selected male courting and mating did not subsequently increase the time they spent near a live target male. These findings provide the first demonstration of which we are aware of birds transferring individual identification from a video sequence to a real animal. Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.      

Female guppies Poecilia reticulata prefer males that can learn fast

The role of learning ability as a potentially desirable male trait in sexual selection was investigated in the guppy Poecilia reticulata . Mate preference tests and the rate at which a male learnt two mazes were used to determine whether female preference was related to male learning ability. In addition, male body size and saturation of the orange patches were measured. Female preference was found to be related to rate of learning, such that males that learnt the mazes faster were found to be more attractive to females, but was not found to be related to body size or saturation.     

Female Maylandia zebra prefer victorious males

Females of a widespread species of the rock-dwelling haplochromine cichlids of Lake Malawi, Maylandia zebra, show preference for males that successfully evict intruding males from their territory. This behaviour, experimentally induced by the investigators in a laboratory setting, was also preferred over males that were not permitted to interact with any other individual.     

Female butterflies prefer males bearing bright iridescent ornamentation

Butterflies are among nature's most colorful animals, and provide a living showcase for how extremely bright, chromatic and iridescent coloration can be generated by complex optical mechanisms. The gross characteristics of male butterfly colour patterns are understood to function for species and/or sex recognition, but it is not known whether female mate choice promotes visual exaggeration of this coloration. Here I show that females of the sexually dichromatic species Hypolimnas bolina prefer conspecific males that possess bright iridescent blue/ultraviolet dorsal ornamentation. In separate field and enclosure experiments, using both dramatic and graded wing colour manipulations, I demonstrate that a moderate qualitative reduction in signal brightness and chromaticity has the same consequences as removing the signal entirely. These findings validate a long-held hypothesis, and argue for the importance of intra- versus interspecific selection as the driving force behind the exaggeration of bright, iridescent butterfly colour patterns.     

Female red deer prefer the roars of larger males

Surprisingly little is known about the role of acoustic cues in mammal female mate choice. Here, we examine the response of female red deer (Cervus elaphus) to male roars in which an acoustic cue to body size, the formants, has been re-scaled to simulate different size callers. Our results show that oestrous red deer hinds prefer roars simulating larger callers and constitute the first evidence that female mammals use an acoustic cue to body size in a mate choice context. We go on to suggest that sexual selection through female mating preferences may have provided an additional selection pressure along with male-male competition for broadcasting size-related information in red deer and other mammals.     

Female sand gobies prefer good fathers over dominant males

Female preference for males successful in male-male competition is generally assumed to result in mating with high quality males. Here I report results from an experiment disentangling the effects of intra- and intersexual selection in the sand goby, Pomatoschistus minutus, a marine fish that exhibits paternal care. I show that large males are successful in male–male competition, but contrary to what one would expect, dominants are not preferred by females and are not better at taking care of the eggs. Female preference, however, correlated with the subsequent hatching success of the eggs. Thus, female choice selects for good parenting. Hence, direct benefits in the form of superior paternal care can explain female choice in this species, supporting a good parent process of sexual selection. However, choosing on the outcome of male–male competition does not enable females to mate with the ''best'' males.     

Female rose bitterling prefer MHC-dissimilar males: experimental evidence

The role of genetic benefits in female mate choice remains a controversial aspect of sexual selection theory. In contrast to "good allele" models of sexual selection, "compatible allele" models of mate choice predict that females prefer mates with alleles complementary to their own rather than conferring additive effects. While correlative results suggest complementary genetic effects to be plausible, direct experimental evidence is scarce. A previous study on the Chinese rose bitterling (Rhodeus ocellatus) demonstrated a positive correlation between female mate choice, offspring growth and survival, and the functional dissimilarity between the Major Histocompatibility Complex (MHC) alleles of males and females. Here we directly tested whether females used cues associated with MHC genes to select genetically compatible males in an experimental framework. By sequentially pairing females with MHC similar and dissimilar males, based on a priori known MHC profiles, we showed that females discriminated between similar and dissimilar males and deposited significantly more eggs with MHC dissimilar males. Notably, the degree of dissimilarity was an important factor for female decision to mate, possibly indicating a potential threshold value of dissimilarity for decision making, or of an indirect effect of the MHC.     

Female stickleback prefer shallow males: Sexual selection on nest microhabitat

Sexual selection is most often thought of as acting on organismal traits, such as size or color. However, individuals’ habitat use may also affect mating success. Here, we show that, in threespine stickleback, nest depth can be a target of sexual selection. In postglacial lakes in British Columbia, male threespine stickleback nest in a narrow range of depths. Prior studies revealed heritable variation in males’ preferred nest microhabitat. We surveyed four natural populations, finding that male stickleback with shallower nests were more successful at breeding. Indeed, nest depth was a much stronger predictor of male mating success than more commonly studied targets of sexual selection in stickleback (size, condition, shape, color, infection status). This selection on nest depth means that variance in fitness changed predictably across microhabitats, altering the opportunity for sexual selection to act on other traits. Accordingly, we show that sexual selection on other male traits is strongest where variance in nesting success is highest (at intermediate nest depths in some lakes). We conclude that males’ choice of nesting microhabitat is an especially important target of sexual selection, resulting in fine‐scale spatial variation in sexual selection on other traits.     

Female collared flycatchers learn to prefer males with an artificial novel ornament

We experimentally investigated whether learning from previousexperiences can lead to the establishment of a new mate preferencein a wild population of birds. During year one (2001), 63 femalecollared flycatchers (Ficedula albicollis) bred together withmales that we had provided with a novel trait, a red stripeon their white forehead patch (a sexually selected trait). Somecolor patterns of birds are largely determined by a few genes,and this experiment was designed to mimic the occurrence ofmutations in such genes. In the subsequent year (2002), we foundthat females with previous experience with red-striped maleswere more likely to pair with red-striped males (76%) than withcontrol males. By contrast, naïve females (i.e., with noprevious experience with red-striped males) were not more likelyto pair with red-striped males (44%) than with control males.Females paired with red-striped males produced more offspringthan females paired with control males, suggesting that maleswith the novel trait had become favored by selection. Thus,female collared flycatchers appear to quickly learn to associatea novel trait with a suitable mate that, in turn, leads to assortativemating between local mates (i.e., males with the new trait andfemales with previous experience of the new trait). Our resultsprovide support for the notion that learning may play an importantrole when the co-evolution of preferences and preferred traitstakes different routes in different populations of the samebird species.     

Female Japanese quail aggregate to avoid sexual harassment by conspecific males: a possible cause of conspecific cueing

In a series of three experiments, we examined the hypothesis that female Japanese quail, Coturnix japonica, are motivated to form aggregations to reduce the probability of harassment by conspecific males. When in the presence of a conspecific male, female quail both sought others of their sex and remained near them. However, if no males were present, females were indifferent to or tended to avoid one another. We interpret these data as consistent with the hypothesis that one function of aggregations of female quail is to avoid harassment by conspecific males. Skew in male mating success would be a probable consequence of such aggregations of females. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Acidification effects on biofouling communities: winners and losers

How ocean acidification affects marine life is a major concern for science and society. However, its impacts on encrusting biofouling communities, that are both the initial colonizers of hard substrata and of great economic importance, are almost unknown. We showed that community composition changed significantly, from 92% spirorbids, 3% ascidians and 4% sponges initially to 47% spirorbids, 23% ascidians and 29% sponges after 100 days in acidified conditions (pH 7.7). In low pH, numbers of the spirorbid Neodexiospira pseudocorrugata were reduced ×5 compared to controls. The two ascidians present behaved differently with Aplidium sp. decreasing ×10 in pH 7.7, whereas Molgula sp. numbers were ×4 higher in low pH than controls. Calcareous sponge (Leucosolenia sp.) numbers increased ×2.5 in pH 7.7 over controls. The diatom and filamentous algal community was also more poorly developed in the low pH treatments compared to controls. Colonization of new surfaces likewise showed large decreases in spirorbid numbers, but numbers of sponges and Molgula sp. increased. Spirorbid losses appeared due to both recruitment failure and loss of existing tubes. Spirorbid tubes are comprised of a loose prismatic fabric of calcite crystals. Loss of tube materials appeared due to changes in the binding matrix and not crystal dissolution, as SEM analyses showed crystal surfaces were not pitted or dissolved in low pH conditions. Biofouling communities face dramatic future changes with reductions in groups with hard exposed exoskeletons and domination by soft‐bodied ascidians and sponges.     

Female tawny-bellied seedeaters do not prefer more colorful males in choice experiments

Plumage coloration has long been studied as a sexually selected character. The tawny-bellied seedeater, Sporophila hypoxantha, is a sexually dichromatic species, with adult males the more colorful sex and juvenile males indistinguishable from females. We did choice experiments to evaluate female preferences for males that differ in age or plumage coloration. Females were evaluated in three experiments: (1) choice between males with similar breast brightness that differed in age, (2) choice between males of 2 years of age that differed in breast brightness, and (3) choice between males of 3 or more years of age that differed in breast brightness. We also repeated the latter experiment with estradiol-treated females. We did not find a clear female preference for brighter or older males, as females spent the same proportion of time with males of similar breast brightness that differed in age or with males of similar age that differed in breast brightness. Our results do not support the hypothesis that breast brightness is a cue used by female tawny-bellied seedeaters at the time of choosing males. We propose that, in this species, male plumage coloration might play a role in intrasexual competition.     

Female zebra finches prefer the songs of males who quickly solve a novel foraging task to the songs of males unable to solve the task

Correlative evidence suggests that high problem‐solving and foraging abilities in a mate are associated with direct fitness advantages, so it would benefit females to prefer problem‐solving males. Recent work has also shown that females of several bird species who directly observe males prefer those that can solve a novel foraging task over those that cannot. In addition to or instead of direct observation of cognitive skills, many species utilize assessment signals when choosing a mate. Here, we test whether females can select a problem‐solving male over a non‐solving male when presented only with a signal known to be used in mate assessment: song. Using an operant conditioning assay, we compared female zebra finch (Taeniopygia guttata) preference for the songs of males that could quickly solve a novel foraging task to the songs of males that could not solve the task. Females were never housed with the test subject males whose song they heard, and the only information provided about the males was their song. We found that females elicited more songs of problem‐solving males than of non‐solvers, indicating that song may contain information about a male’s ability to solve a novel foraging task and that naïve females prefer the songs of problem‐solving males.     

The effects of changing climate on faunal depth distributions determine winners and losers

Changing climate is predicted to impact all depths of the global oceans, yet projections of range shifts in marine faunal distributions in response to changing climate seldom evaluate potential shifts in depth distribution. Marine ectotherms' thermal tolerance is limited by their ability to maintain aerobic metabolism (oxygen‐ and capacity‐limited tolerance), and is functionally associated with their hypoxia tolerance. Shallow‐water (<200 m depth) marine invertebrates and fishes demonstrate limited tolerance of increasing hydrostatic pressure (pressure exerted by the overlying mass of water), and hyperbaric (increased pressure) tolerance is proposed to depend on the ability to maintain aerobic metabolism, too. Here, we report significant correlation between the hypoxia thresholds and the hyperbaric thresholds of taxonomic groups of shallow‐water fauna, suggesting that pressure tolerance is indeed oxygen limited. Consequently, it appears that the combined effects of temperature, pressure and oxygen concentration constrain the fundamental ecological niches (FENs) of marine invertebrates and fishes. Including depth in a conceptual model of oxygen‐ and capacity‐limited FENs' responses to ocean warming and deoxygenation confirms previous predictions made based solely on consideration of the latitudinal effects of ocean warming (e.g. Cheung et al., 2009), that polar taxa are most vulnerable to the effects of climate change, with Arctic fauna experiencing the greatest FEN contraction. In contrast, the inclusion of depth in the conceptual model reveals for the first time that temperate fauna as well as tropical fauna may experience substantial FEN expansion with ocean warming and deoxygenation, rather than FEN maintenance or contraction suggested by solely considering latitudinal range shifts.     

Female Iberian wall lizards prefer male scents that signal a better cell-mediated immune response

In spite of the importance of chemoreception in sexual selection of lizards, only a few studies have examined the composition of chemical signals, and it is unknown whether and how chemicals provide honest information. Chemical signals might be honest if there were a trade-off between sexual advertisement and the immune system. Here, we show that proportions of cholesta-5,7-dien-3-ol in femoral secretions of male Iberian wall lizards (Podarcis hispanica) were related to their T-cell-mediated immune response. Thus, only males with a good immune system may allocate higher amounts of this chemical to signalling. Furthermore, females selected scents of males with higher proportions of cholesta-5,7-dien-3-ol and lower proportions of cholesterol. Thus, females might base their mate choice on the males' quality as indicated by the composition of their chemical signals.     

Inter-individual variability during morning choruses in Japanese quail males (Coturnix coturnix japonica)

We compared the organization of dawn choruses in five groups of Japanese quail, Coturnix coturnix japonica, males (four groups of kin-related males and one group of unrelated males). We documented the structure of chorus groups: one male sang much more than the others during the dawn peak in four of the five groups, and this regardless of the number of males in the group. The dominant singers were then removed from two similar-sized groups, one of kin-related (K3) and the other of unrelated (NK) males. The quantity of song emitted by the remaining NK males was modified, but not that emitted by the K3 males.