Andromonoecy and fruit set in three genera of the Proteaceae

It has been suggested by some authors that the low fruit to flower ratio in some Proteaceae is due to andromonoecy, while others, looking particularly at Banksia , have not been able to find evidence for male flowers in the inflorescences. Stirlingia latifolia, Xylomelum occidentals and X. angustifolium are clearly andromonoecous, while no evidence for this condition could be found in Brabejum stellatifoliutn. Production of fertile fruit is related to andromonoecy in Xylomelum and S. latifolia but not in Brabejum. It is unlikely that all-encompassing solutions will be found to what initially seem to be widespread traits in the family, especially in regard to pollination biology, as the genera in the family occupy widely different environments and have very diverse ecological ranges.     

A comparative study of breeding seasonality and litter size in eleven taxa of captive lemurs (Lemur andVarecia)

Breeding records of 11 taxa of captive lemurs housed at the Duke University Primate Center (DUPC), North Carolina, were analyzed for differences in the timing of births, for the relationship between breeding season and photoperiod, and for differences in litter size. At DUPC there are significant differences in the timing of births among certain taxa, including differences among some subspecies of Lemur fulvus.However, changes in latitude result in changes in the timing of the breeding season. Lemurs moved to higher latitudes mate at lower light-dark ratios than on Madagascar. The data presented here are consistent with the following model: a photoperiodic cue initiating reproductive activity, presumably a light-dark threshold, precedes the actual mating season by approximately 2 months, with an intervening period of physiological and social preparation. On Madagascar, selection may have favored births that coincide with the end of dry seasons and the beginning of wet seasons, which results in lactation and weaning during times of resource abundance. Taxa from the north and east have the highest mean litter sizes; those from the west have the lowest.     

Isolation and characterization of microsatellites in Pacific white shrimp Penaeus (Litopenaeus) vannamei

Five polymorphic microsatellite loci were characterized for Penaeus (Litopenaeus) vannamei. Loci were isolated using a partial Sau3A1 genomic library by the sequencing of randomly selected clones and by a biotinylated (CT)₁₀ and (GT)₁₀ probes screening procedure. The last strategy resulted in the most useful data. About 40% of the clones showed a previously reported satellite/microsatellite (PVS1), reducing the chance of finding new microsatellite regions. Whereas two of the microsatellite loci with more than 10 alleles will be useful for mating analysis in a breeding program, the others might prove useful for population genetic studies.     

Characterization of polymorphic microsatellite markers for the Carnaby's cockatoo (Calyptorhynchus latirostris) and related black cockatoo species

Microsatellite loci were isolated from Carnaby's black cockatoo (Calyptorhynchus latirostris: Aves), a highly valued, endangered, and endemic species of bird from Western Australia. This study describes three dinucleotide and one tetranucleotide microsatellite loci for which the primers produced clear and polymorphic amplification patterns with between two and nine alleles and moderate levels of variability. Two additional dinucleotide markers which were monomorphic in the Carnaby's cockatoo were able to amplify and were polymorphic in two other species of black cockatoo, greatly increasing the utility of these markers.     

Optimal reproductive phenology under size‐dependent cannibalism

Intra‐cohort cannibalism is an example of a size‐mediated priority effect. If early life stages cannibalize slightly smaller individuals, then parents face a trade‐off between breeding at the best time for larval growth or development and predation risk from offspring born earlier. This game‐theoretic situation among parents may drive adaptive reproductive phenology toward earlier breeding. However, it is not straightforward to quantify how cannibalism affects seasonal egg fitness or to distinguish emergent breeding phenology from alternative adaptive drivers. Here, we devise an age‐structured game‐theoretic mathematical model to find evolutionary stable breeding phenologies. We predict how size‐dependent cannibalism acting on eggs, larvae, or both changes emergent breeding phenology and find that breeding under inter‐cohort cannibalism occurs earlier than the optimal match to environmental conditions. We show that emergent breeding phenology patterns at the level of the population are sensitive to the ontogeny of cannibalism, that is, which life stage is subject to cannibalism. This suggests that the nature of cannibalism among early life stages is a potential driver of the diversity of reproductive phenologies seen across taxa and may be a contributing factor in situations where breeding occurs earlier than expected from environmental conditions.     

Smallholder experiences with dairy cattle crossbreeding in the tropics: from introduction to impact

Crossbreeding of indigenous tropical and improved western dairy cattle breeds as tool to improve dairy cattle performance on smallholder farms has been widely advocated, criticised and yet applied. The government of Ethiopia supported this technology for decades but adoption rate is low. Constraints are documented but there is little information about farm level introduction and development of crossbreeding. A total 122 smallholders with mixed crop livestock farms and at least 8 years of successful crossbreeding were interviewed using a pre-tested questionnaire in two contexts in Amhara Regional state in north-western Ethiopia. Crossbreeding initiator was either uncoordinated government extension or a coordinated development project, also implemented with governmental support. Qualitative and quantitative data on farmers’ motivations, crossbreeding introduction, initiator support, breeding adaptation and impacts at farm level were analysed. Results show that even though motives vary between contexts the underlying reason to introduce crossbreeding was economic profit. To be able to introduce crossbreeding support of initiators (e.g. extension) and other farmers was essential. The crossbreeding introduction context had some influence. Governmental actors were the main source of support and supplier of exotic genetics but the farmer network acted as safety net filling gaps of government support. Breeding strategies focused on performance increase. A lack of basic understanding of crossbreeding has been identified. A surprising, probably biased, result was general satisfaction with initiator support and with breeding services. It was challenged by the high proportion of farmers unable to follow a breeding strategy due to insufficient bull and/or semen supply. Crossbreeding changed the smallholder production system to a high input – high output system. Except for crossbred adaptation problems, challenges were ranked context specific and influenced by the initiator. Farmers perceived crossbreeding as success and recommended it. We conclude that farmers can realize income increase with crossbreeding. The complexity of this technology, high initial investment and the need for support services and external production inputs are probable reasons why crossbreeding uptake is low. Improving the availability of semen and/or bulls must be the top priority for breeding service providers to enable farmers to follow a breeding strategy and reach a suitable and sustainable herd performance. Access to investment capital, input supply, strong technical support and market linkages are crucial for successful crossbreeding.     

Imprints of glacial history and current environment on correlations between endemic plant and invertebrate species richness

Aim We evaluate how closely diversity patterns of endemic species of vascular plants, beetles, butterflies, molluscs and spiders are correlated with each other, and to what extent similar environmental requirements or survival in common glacial refugia and comparable dispersal limitations account for their existing congruence. Location Austria. Methods We calculated pairwise correlations among species numbers of the five taxonomic groups in 1405 cells of a 3′ × 5′ raster (c. 35 km²) using the raw data as well as the residuals of regression models that accounted for: (1) environmental variables, (2) environmental variables and the occurrence of potential refugia during the Last Glacial Maximum, or (3) environmental variables, refugia and spatial filters. Results Pairwise cross‐taxonomic group Spearman’s rank correlations in the raw data were significantly positive in most cases, but only moderate (0.3 < ρ < 0.5) to weak (ρ < 0.3) throughout. Correlations were closest between plants and beetles, plants and butterflies, and plants and snails, respectively, whereas the distribution of endemic spiders was largely uncorrelated with those of the other groups. Environmental variables explained only a moderate proportion of the variance in endemic richness patterns, and the response of individual groups to environmental gradients was only partly consistent. The inclusion of refugium locations and the spatial filters increased the goodness of model fit for all five taxonomic groups. Moreover, removing the effects of environmental conditions reduced congruence in endemic richness patterns to a lesser extent than did filtering the influence of refugium locations and spatial autocorrelation, except for spiders, which are probably the least dispersal‐limited of the five groups. Main conclusions The moderate to weak congruence of endemic richness patterns clearly limits the usefulness of a surrogacy approach for designating areas for the protection of regional endemics. On the other hand, our results suggest that dispersal limitations still shape the distributions of many endemic plant, snail, beetle and butterfly species, even at the regional scale; that is, survival in shared refugia and subsequent restricted spread retain a detectable signal in existing correlations. Concentrating conservation efforts on well‐known Pleistocene refugia hence appears to be a reasonable first step towards a strategy for protecting regional endemics of at least the less mobile invertebrate groups.     

Use of molecular markers in participatory plant breeding: assessing the genetic variability in cotton populations bred by farmers

In participatory plant breeding, farmers are involved in simple selection schemes that are not suitable for assessing genetic variability in the segregating populations. We propose to use information derived from molecular marker analyses to help monitoring such populations. In this study, we used three indicators to compare genetic variability in eight genetic structures, that is three plant populations selected by farmers over five generations, three nonselected populations and two commercial varieties. The three indicators were the polymorphic locus rate, heterozygosity rate and dissimilarity index. The results highlighted that the genetic variability decreased more with farmers’ selection than with environmental factors. The breeding process was not complete because genetic variability in the selected populations was midway between that of the nonselected populations and that of the commercial varieties monitored. The three proposed indicators were relevant for describing the studied populations. They could be interpreted according to a grid drawn up on the basis of the results of the present study.