Capital and income breeding traits differentiate trophic match–mismatch dynamics in large herbivores

For some species, climate change has altered environmental conditions away from those in which life-history strategies evolved. In such cases, if adaptation does not keep pace with these changes, existing life-history strategies may become maladaptive and lead to population declines. We use life-history theory, with a specific emphasis on breeding strategies, in the context of the trophic match–mismatch framework to form generalizable hypotheses about population-level consumer responses to climate-driven perturbations in resource availability. We first characterize the income and breeding traits of sympatric caribou and muskoxen populations in western Greenland, and then test trait-based hypotheses about the expected reproductive performance of each population during a period of high resource variability at that site. The immediate reproductive performance of income breeding caribou decreased with trophic mismatch. In contrast, capital breeding muskoxen were relatively unaffected by current breeding season resource variability, but their reproductive performance was sensitive to resource conditions from previous years. These responses matched our expectations about how capital and income breeding strategies should influence population susceptibility to phenological mismatch. We argue for a taxon-independent assessment of trophic mismatch vulnerability based on a life-history strategy perspective in the context of prevailing environmental conditions.     

Play in a captive breeding colony of harbour seals (Phoca vitulina): constrained by time or by energy?

The play of a breeding colony of captive harbour seals ( Phoca vitulina) was documented over a four-year period to identify changes associated with seasonal variations in energy use, and to corroborate previous field studies which were restricted to observations at the hauling grounds during breeding and moulting. Outside the breeding/moulting period, play was more frequent and in some animals average daily food intake was higher. Thyroid hormones did not vary seasonally in any clear manner. The adults increased their daily activity markedly during the breeding/moulting period. It is argued that these changes in play rate were a reflection of constraints on time rather than energy, since the animals played most when mass and fat were being accumulated for the winter. Field observations were confirmed in the laboratory, showing most play to be solitary, with significant amounts of adult play which was more stereotyped than that of younger seals. Behaviour in captivity was less ebullient and sometimes truncated in comparison to that seen in the wild; however, nine new types of play and a more elaborate repertoire of object play were seen in the laboratory, where seals could be observed throughout the year and underwater.     

Paying to stay or paying to breed? Field evidence for direct benefits of helping behavior in a cooperatively breeding fish

Several hypotheses aim to explain the evolution of helping behavior,but conclusive experimental support for evaluating the relativeimportance of individual hypotheses is still lacking. We reporton two field experiments conducted to test the "territory inheritance"and "pay-to-stay" hypotheses in the cooperatively breeding cichlidfish Neolamprologus pulcher The territory inheritance hypothesiswas tested by removing one parent, which created breeding vacancies.In 39% of cases, same-sex helpers took over the breeding spot;in 44% of cases helpers continued helping new breeders, and17% were evicted by new breeders. Helpers that were closelysize matched to the removed breeder had a better chance of gainingthe breeding spot Male helpers tended to continue helping aftera takeover more often than females.The pay-to-stay hypothesiswas tested-by temporarily removing helpers. Whereas breedersdid not respond aggressively to removals, other group membersattacked the removed helpers on their return, and 29% were eventuallyevicted. The returning helpers assisted more by increasing theirrate of territory maintenance and defense and visiting the broodchamber more frequently Size and sex of removed helpers didnot explain the observed aggressive reactions of other groupmembers. Thus, our results support both hypotheses: N. pulcherneeds to pay with help to be allowed to remain protected inthe family group, and there they may inherit the natal territory.N. pulcher helpers gain direct benefits from helping behavior.     

Sex ratio variation and mixed pairs in roe deer: evidence for control of sex allocation?

Sex allocation has provided rich ground for the development of evolutionary theory. The dominant models in vertebrates have provided predictions of sex ratio based on asymmetry in variance in breeding success between sexes in the breeding system, and the relative effect of local competition. In ungulates, empirical work has provided some support for these models, but has also generated apparently contradictory observations. Recent models have provided some predictions for both individual and population sex ratio, showing that the availability of high-quality habitat patches and dispersal rates can critically affect both population- and individual-level expectations. We explore patterns in offspring sex ratio among a large sample of roe deer, a species with some interesting aspects of the breeding system. We found that in singleton pregnancies (the minority) there was an excess of male embryos, which was more marked in does in good condition at most sites. While the sex ratio among twins was close to parity, and unaffected either by average condition among populations or by individual condition within populations, we observed a clear excess of mixed pregnancies (sub-binomial variance, SBV). The excess was greater where the average condition was high. Within sites, population changes in average condition were associated with changes in SBV: in populations declining in condition, SBV also declined. There was no tendency for mixed twins to be more likely in individuals in better condition within a population. We conclude that condition-dependent allocation of sex does occur in roe deer. We suggest that in these "income breeders", mixed pairs might offer the greatest opportunity to optimize maternal investment during lactation, when conditions will be unpredictable, and that this is increasingly the case when average condition is poor.     

Snakes allocate amino acids acquired during vitellogenesis to offspring: are capital and income breeding consequences of variable foraging success?

Reproductive allocation strategies have been historically described as lying on a continuum between capital and income breeding. Capital breeders have been defined as species that allocate stored reserves to reproduction, whereas income breeders have been defined as species that allocate relatively recently‐ingested food resources to reproduction. Snakes are considered capital breeders because they efficiently store large amounts of nutrients and energy, potentially enough to support an entire reproductive bout without feeding. We examined the abilities of five viviparous snake species to allocate income to follicles during vitellogenesis. We fed ¹⁵N‐labelled L‐leucine to experimental females of each species during vitellogenesis, whereas control females were fed unlabelled meals. After ovulation, we measured yolk ¹⁵N p.p.m. using mass spectrometry. Maternal scale samples taken before labelling were used to estimate endogenous ¹⁵N concentrations, which should represent ‘capital’. Scale samples taken at ovulation were used to determine whether snakes assimilated ¹⁵N‐labelled‐leucine from labelled diets. Yolks and post‐ovulatory scales of labelled females were significantly more enriched in ¹⁵N than those of unlabelled females in all species, indicating significant assimilation and allocation of income‐derived amino acids to the yolk during vitellogenesis. The lack of among‐species differences suggests that all species allocated income amino acids to vitellogenesis. The results obtained in the present study suggest that proportional utilization of income or capital depends on the frequency and timing of foraging success during reproductive events. Therefore, capital and income breeding may be consequences of both life‐history and environmental constraints on foraging success, rather than strategies of reproductive allocation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 390–404.     

Colour diversification in Malawi cichlids: evidence for adaptation,reinforcement or sexual selection?

The mechanisms responsible for the explosive radiations of haplochromine cichlid fishes in Africa's great lakes remain controversial. Since species thought to be closely related often differ most apparendy in male breeding colours, I examined patterns of male colour variation in rock-dwelling cichlids from Lake Malawi to test whether initial divergence between species is likely to have been caused by adaptation to differing habitats, by selection against hybridization (reinforcement or character displacement), or by sexual selection. I found that all significant variation in overall male colour occurs within, not between, species complexes, in contrast to variation in habitat and behavioural traits, which differed significandy between complexes. Male colour does not vary significandy with habitat characteristics such as water depth, and sympatric species differ no more in colour than allopatric ones. These results fail to provide support for adaptation or reinforcement as initial causes of colour divergence, and are consistent with the possibility that divergence may instead have been caused by sexual selection, but a direct test of sexual selection is not yet possible.     

Intrasexual competition in females: evidence for sexual selection?

In spite of recent interest in sexual selection in females, debate exists over whether traits that influence female-female competition are sexually selected. This review uses female-female aggressive behavior as a model behavioral trait for understanding the evolutionary mechanisms promoting intrasexual competition, focusing especially on sexual selection. I employ a broad definition of sexual selection, whereby traits that influence competition for mates are sexually selected, whereas those that directly influence fecundity or offspring survival are naturally selected. Drawing examples from across animal taxa, including humans, I examine 4 predictions about female intrasexual competition based on the abundance of resources, the availability of males, and the direct or indirect benefits those males provide. These patterns reveal a key sex difference in sexual selection: Although females may compete for the number of mates, they appear to compete more so for access to high-quality mates that provide direct and indirect (genetic) benefits. As is the case in males, intrasexual selection in females also includes competition for essential resources required for access to mates. If mate quality affects the magnitude of mating success, then restricting sexual selection to competition for quantity of mates may ignore important components of fitness in females and underestimate the role of sexual selection in shaping female phenotype. In the future, understanding sex differences in sexual selection will require further exploration of the extent of mutual intrasexual competition and the incorporation of quality of mating success into the study of sexual selection in both sexes.     

Rethinking classic starling displacement experiments: evidence for innate or for learned migratory directions?

In an attempt to encourage the discourse on sources of individual variation in seasonal migration patterns and the microevolution of bird migration, we here critically examine the published interpretations of a now classic displacement study with starlings Sturnus vulgaris. Based on the ring recoveries after experimental displacement towards the south and southeast of Dutch capture sites of over 18 000 hatch-year and older starlings, in a series of analyses published in Ardea from 1958 to 1983, A. C. Perdeck established that displaced starlings showed appropriately changed orientations only when they were experienced. During both southward and northward migration, released adults navigated to an apparently previously learned goal (i.e. the wintering or the breeding area) by showing appropriately changed orientations. Juveniles showed appropriate directions when returning to the breeding grounds. In contrast, during their first southward migration displaced juveniles carried on in the direction (and possibly the distance) expected for their release at the Dutch capture site. From the mid-1970s this work has become cited as evidence for starlings demonstrating ‘innate’ migratory directions. If the definition of innateness is ‘not learned by the individual itself’, then there is a range of non-innate influences on development that are not ruled out by Perdeck's experimental outcomes. For example, young starlings might have carried on in the direction that they learned to migrate before being caught, e.g. by observing the migratory directions of experienced conspecifics. We argue that, despite over 60 citations to Perdeck as demonstrating innate migratory directions, the jury is out.     

Dual-immunohistochemistry provides little evidence for epithelial–mesenchymal transition in pulmonary fibrosis

epithelial–mesenchymal transition (EMT) has been considered to be involved in organ fibrogenesis. However, there is few direct evidence of this process in the pathophysiology of pulmonary fibrosis in vivo. Therefore, we tried to verify the involvement of this process in the development of pulmonary fibrosis. Since the co-expressions of epithelial and mesenchymal markers are thought to be a marker of EMT, we performed dual-immuunohistochemistry to assess the co-expressions of these proteins in lung tissues from bleomycin-induced pulmonary fibrosis in mice, and from patients with idiopathic pulmonary fibrosis, and nonspecific interstitial pneumonia. Double positive cells for epithelial markers including E-cadherin, T1α, or aquaporin 5, and a mesenchymal markers α-smooth muscle actin or vimentin were not found in bleomycin-induced pulmonary fibrosis in mice. Double positive cells for E-cadherin, ICAM-1, LEA, CD44v9, or SP-A and α-smooth muscle actin or vimentin were not found in lung tissues from normal lung parenchyma, idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia. These results offer at least two possibilities. One is that EMT does not occur in IPF or bleomycin-induced pulmonary fibrosis in mice. Another is that EMT may occur in pulmonary fibrosis but the time during this transition in which cells express detectable levels of epithelial and mesenchymal markers is too small to be detected by double immunohistochemistry.     

Could Miscanthus replace maize as the preferred substrate for anaerobic digestion in the United Kingdom? Future breeding strategies

Fodder maize is the most commonly used crop for biogas production owing to its high yields, high concentrations of starch and good digestibility. However, environmental concerns and possible future conflict with land for food production may limit its long‐term use. The bioenergy grass, Miscanthus, is a high‐yielding perennial that can grow on marginal land and, with ‘greener’ environmental credentials, may offer an alternative. To compete with maize, the concentration of non‐structural carbohydrates (NSC) and digestibility may need to be improved. Non‐structural carbohydrates were quantified in 38 diverse genotypes of Miscanthus in green‐cut biomass in July and October. The aim was to determine whether NSC abundance could be a target for breeding programmes or whether genotypes already exist that could rival maize for use in anaerobic digestion systems. The saccharification potential and measures of N P and K were also studied. The highest concentrations of NSC were in July, reaching a maximum of 20% DW. However, the maximum yield was in October with 300–400 g NSC plant^?1 owing to higher biomass. The digestibility of the cell wall was higher in July than in October, but the increase in biomass meant yields of digestible sugars were still higher in October. Nutrient concentrations were at least twofold higher in July compared to November, and the abundance of potassium showed the greatest degree of variation between genotypes. The projected maximum yield of NSC was 1.3 t ha^?1 with significant variation to target for breeding. Starch accumulated in the highest concentrations and continued to increase into autumn in some genotypes. Therefore, starch, rather than sugars, would be a better target for breeding improvement. If harvest date was brought forward to autumn, nutrient losses in non‐flowering genotypes would be comparable to an early spring harvest.     

Re-orienting in space: do animals use global or local geometry strategies?

Here we compare whether birds encode surface geometry using principal axes, medial axes or local geometry. Birds were trained to locate hidden food in two geometrically identical corners of a rectangular arena and subsequently tested in an L-shaped arena. The chicks showed a primary local geometry strategy, and a secondary medial axes strategy, whereas the pigeons showed a medial axes strategy. Neither species showed behaviour supportive of the use of principal axes. This is, to our knowledge, the first study to directly examine these three current theories of geometric encoding.     

Defence strategies against a parasitoid wasp in Drosophila: fight or flight?

Hosts may defend themselves against parasitism through a wide variety of defence mechanisms, but due to finite resources, investment in one defence mechanism may trade-off with investment in another mechanism. We studied resistance strategies against the parasitoid wasp Leptopilina boulardi in two Drosophila species. We found that D. melanogaster had significantly lower physiological resistance against L. boulardi than D. simulans, and hypothesized that D. melanogaster might instead invest more heavily in other forms of defence, such as behavioural defence. We found that when given a choice between clean oviposition sites and sites infested with wasps, both D. melanogaster and D. simulans detected and avoided infested sites, which presumably limits later exposure of their offspring to infection. Unlike D. simulans, however, D. melanogaster laid significantly fewer eggs than controls in the forced presence of wasps. Our findings suggest that D. melanogaster relies more heavily on behavioural avoidance as defence against wasp parasitism than D. simulans, and that this may compensate for a lack of physiological defence.     

Genome editing in livestock: Are we ready for a revolution in animal breeding industry?

Genome editing is a powerful technology that can efficiently alter the genome of organisms to achieve targeted modification of endogenous genes and targeted integration of exogenous genes. Current genome-editing tools mainly include ZFN, TALEN and CRISPR/Cas9, which have been successfully applied to all species tested including zebrafish, humans, mice, rats, monkeys, pigs, cattle, sheep, goats and others. The application of genome editing has quickly swept through the entire biomedical field, including livestock breeding. Traditional livestock breeding is associated with rate limiting issues such as long breeding cycle and limitations of genetic resources. Genome editing tools offer solutions to these problems at affordable costs. Generation of gene-edited livestock with improved traits has proven feasible and valuable. For example, the CD163 gene-edited pig is resistant to porcine reproductive and respiratory syndrome (PRRS, also referred to as “blue ear disease”), and a SP110 gene knock-in cow less susceptible to tuberculosis. Given the high efficiency and low cost of genome editing tools, particularly CRISPR/Cas9, it is foreseeable that a significant number of genome edited livestock animals will be produced in the near future; hence it is imperative to comprehensively evaluate the pros and cons they will bring to the livestock breeding industry. Only with these considerations in mind, we will be able to fully take the advantage of the genome editing era in livestock breeding.     

Manipulating anonymity: Streetwalkers’ strategies for safety in the city*

Gender must be understood as a domain of social practice with its own structure and dynamics. An outline of a relational account of gender is given, emphasizing the multiple structures of gender and the way bodies are drawn into social practice. Emerging research on masculinity can best be understood through such an approach, which allows the multiplicity of masculinities, and their interrelations, to be traced. Two case studies are outlined: theoretical work on the relations between masculinities and state institutions, and field research on working‐class masculinities under structural unemployment.     

Monogeneans in introduced and native cichlids in México: evidence for transfer

We examined 2 cichlid fish species native to México, Cichlasoma callolepis and C. fenestratum, and 2 introduced African cichlids, Oreochromis aureus and O. niloticus, from 3 localities in southeastern México for monogeneans. Six monogenean species infected the African cichlids: Cichlidogyrus haplochromii, C. dossoui, C. longicornis longicornis, C. sclerosus, C. tilapiae, and Enterogyrus malmbergi. We found all these parasite species, except C. haplochromii and C. dossoui, on the native C. fenestratum and C. callolepis. Prevalences of Cichlidogyrus spp. were 3-10% and abundances ranged from 0.03 +/- 0.2 to 0.1 +/- 0.3 for native cichlids. We only recovered a single E. malmbergi from 1 C. callolepis. We found Sciadicleithrum bravohollisae, a monogenean of native Cichlasoma spp., on the gills of the introduced O. aureus from Lake Catemaco (prevalence 3%, abundance 0.03 +/- 0.2). Although prevalence and abundance in atypical hosts were fairly low, the present findings provide evidence of monogenean transfer from African to American cichlids and vice versa. This is the first record of exotic monogeneans in the genus Cichlidogyrus and Enterogyrus infecting native American cichlid fish. It is also the first record from southeastern México of a native American monogenean infecting introduced African cichlids.     

Newly arrived or previously overlooked: is there evidence for climate-driven changes in the distribution of molluscs in the Barents Sea?

In recent years, there have been frequent reports of invertebrate species newly recorded from particular areas of the Northeastern Atlantic, and it has often been suggested that these are the result of changes in species ranges due to recent warming. These suggestions make three assumptions: (1) that we have a good knowledge of the fauna of these areas; (2) that new records of “southern” species are more frequent than new records of “northern” species; (3) that climate change is the only factor affecting species range. I tested these assumptions on published records of 30 benthic molluscan species which have been found alive for the first time in the Russian part of the Barents Sea since 2006. Some of the discussed species are warm-water species and may have extended their ranges northward in response to climate change. However, our baseline knowledge of the molluscan fauna of this area before 2006 is limited by the frequent lack of molluscan specialists to study the available material, by the frequent lack of detailed publication and by changes in sampling and processing methods. New records of “southern” species are in fact not significantly commoner than new records of “northern” species. Also reasons other than climate change for observed changes in species distribution should be considered.     

Plumage variability and territoriality in breeding turnstone Arenaria interpres: status signalling or individual recognition?

The turnstone Arenaria interpres has marked plumage variability in comparison with many other waders (shorebirds). Two hypotheses were tested in an attempt to explain plumage variability in breeding turnstones. The first, the status signalling hypothesis (SSH), suggests that plumage type signals status, and the second, the individual recognition hypothesis (IRH), suggests that plumage differences enable territorial birds to be recognized by their neighbours. The SSH was rejected by two tests: (a) there was no correlation between plumage phenotype of males and the quality of the territories they occupied; and (b) there was no correlation between the plumage phenotype of males and females paired to each other (assuming assortative mating according to rank). The IRH was supported by a test which showed that males could discriminate between neighbours and strangers on plumage differences alone: fibre-glass models mimicking neighbours were effectively ignored whilst models mimicking strangers elicited an aggressive response. It is stressed that this result does not demonstrate that plumage variability in breeding turnstones evolved to facilitate recognition by neighbours, and the potential of the IRH as an explanation of breeding plumage variability in waders is discussed.