Distribution and Habitat Associations of Baboons (Papio hamadryas) in Central Eritrea

At least three diurnal primate taxa are still present in Eritrea, NE Africa: hamadryas baboons (Papio hamadryas hamadryas), olive baboons (Papio h. anubis) and grivet monkeys (Chlorocebus aethiops aethiops). However, information on status and distribution of primates and their habitats in Eritrea is outdated and incomplete. We conducted a primate survey, focussing on hamadryas baboons, to obtain data which will be integrated in a national wildlife management and conservation plan in Eritrea. We obtained information about the geographical distribution and abundance of baboons, their altitudinal range, habitat quality of their home-ranges, aggregation sizes at sleeping cliffs and predator presence. We described habitat quality via the Normalized Difference Vegetation Index (NDVI), a vegetation classification of Landsat MSS satellite data. Hamadryas and olive baboons are still present in Eritrea in ample numbers. Their geographical distributions in 1997 and 1998 did not deviate significantly from their historical distributions. An estimated 15,000 Papio hamadryas hamadryas lived in the 25,000-km² area of survey (0.58 baboons/km²). Population densities of hamadryas baboons in many parts of the survey area are higher than at Kummer's (1968) study site in Ethiopia. Hamadryas baboons live at all altitudes in four of five ecogeographical zones of Eritrea. Olive baboons replaced them in the western lowlands. Both baboon taxa tend to select better quality habitats, characterized by a higher normalized difference vegetation index (NDVI) than the average for the respective ecogeographical zones. Hamadryas baboons show a greater ecological plasticity than olive baboons, which are confined to riverbeds with extended gallery forest. By the end of 1999, a hybrid zone could not be confirmed.     

Size and mating success in males of the western harvester ant,Pogonomyrmex occidentalis (Hymenoptera: Formicidae)

Mating success in males of the lek mating ant species,Pogonomyrmex occidentalis, increases with increased body size. We estimated the magnitude of the selection coefficients on components of size by collecting males in copula and comparing their morphology to that of males that were collected at the lek but that were not mating. Four characters, body mass, head width, wing length, and leg length, were measured for a sample of 225 mating and 324 nonmating males and 225 females. Significant direct selection favors increased wing length and leg length. Multiple regression of transformed variables (principal components) indicated that the increased mating success of larger males is a function of all four characters. We found no evidence of positive assortative mating on the basis of any individual character or on the multivariate general size variable (the first principal component).     

花绒寄甲的交配能力及多次交配对生殖产量的影响

花绒寄甲Dastarcus helophoroides Fairmaire为天牛类蛀干害虫的优势天敌昆虫,为明确该成虫的交配能力和多次交配行为在该虫种群繁衍中的作用,本研究评估了该虫在室内恒定条件下的性成熟期、交配次数、交配持续期和交配间隔期,以及通过设置交配1次、5次、10次和自由交配等4个处理,探讨了多次交配行为对成虫生殖产量的影响。结果表明,花绒寄甲的性成熟期平均为29.35±0.34 d,交配发生时间主要集中在18:00 pm-2:00 am。在观察期内该虫的平均交配次数为4.49±0.24次,其平均交配持续期为9.27±0.12 min,平均交配间隔期为8.60±0.26 d,且随交配次数的增加呈明显缩短趋势。此外,该虫的产卵量随交配次数的增加从交配1次的227.45±15.32粒/雌增加至自由交配的1 426.03±113.71粒/雌,孵化率从交配1次的68.93%±1.47%增加至自由交配的94.98%±0.90%,这些结果证实了花绒寄甲属典型的夜行性、收入型生殖的、多次交配的昆虫种类,交配能力较弱,但多次交配明显提高了该虫的生殖产量,从而支持精子补充假说。     

Inbreeding,heterozygosity, and lymphoma risk among the baboons (Papio hamadryas) of Sukhumi,USSR

This paper describes the spread of lymphoma through a baboon (Papio hamadryas) colony in the Institute of Experimental Pathology and Therapy at Sukhumi, USSR. In the late 1960s, Soviet scientists inoculated 12 baboons with cells from hospitalized human leukemia patients, causing the death of a total of 135 animals between 1967 and 1978. The death rate from lymphoma averages almost 12 baboons per year in the Sukhumi colony. Genetic investigations of these baboons revealed the following: 1) Six blood protein markers out of 16 systems (38%) tested were polymorphic; 2) the average inbreeding coefficient for the entire colony (N = 1,226) was 0.027 (exclusion of baboons with F values equal to 0.0 raised the mean inbreeding coefficient to 0.096); 3) no relationship between inbreeding and risk of lymphoma was noted; and 4) there was an apparent association between both PGM loci and the incidence of lymphoma at the 0.005 levels of significance. This association was further supported by the significantly lower incidence of PGM2 (2-1) genotype in baboons with high anti-VCA-HVP titers.     

Evolution of Primate Social Systems

We review evolutionary processes and mechanisms that gave rise to the diversity of primate social systems. We define social organization, social structure and mating system as distinct components of a social system. For each component, we summarize levels and patterns of variation among primates and discuss evolutionary determinants of this variation. We conclude that conclusive explanations for a solitary life and pair-living are still lacking. We then focus on interactions among the 3 components in order to identify main targets of selection and potential constraints for social evolution. Social organization and mating system are more closely linked to each other than either one is to social structure. Further, we conclude that it is important to seek a priori measures for the effects of presumed selective factors and that the genetic contribution to social systems is still poorly examined. Finally, we examine the role of primate socio-ecology in current evolutionary biology and conclude that primates are not prominently represented because the main questions asked in behavioral ecology are often irrelevant for primate behavior. For the future, we see a rapprochement of these areas as the role of disease and life-history theory are integrated more fully into primate socio-ecology.     

Effects of delayed mating and male mating history on longevity and reproductive performance of the rice stem borer, Chilo suppressalis (Walker) (Lep., Pyralidae)

Abstract:  The mating potential, effects of delayed mating and male mating history on longevity and reproductive performance of female rice stem borer (RSB), Chilo suppressalis , were investigated under laboratory conditions. Given the opportunity, RSB males copulated an average of 2.7 times, while females generally mated only once. Females were more severely affected by mating delay than males in terms of female longevity and reproductive performance. With increasing age at mating, females' longevity increased, while oviposition period, fecundity and egg fertility decreased. Mean fecundity and egg fertility of females mated 1 and 7 days after emergence were 251.3% and 99.2%, and 96.2% and 75.5% respectively. Both were reduced significantly when female mating was delayed beyond 4 days after emergence. However, irrespective of the first mating age and different mating history of the males, the results indicated that both did not result in a significant difference in the quality of their contributions to female longevity and reproductive performance. The results obtained in this study are discussed in relation to the potential effect on pheromone control of RSB.     

Fecundity selection predicts Bergmann's rule in syngnathid fishes

The study of latitudinal increases in organismal body size (Bergmann's rule) predates even Darwin's evolutionary theory. While research has long concentrated on identifying general evolutionary explanations for this phenomenon, recent work suggests that different factors operating on local evolutionary timescales may be the cause of this widespread trend. Bergmann's rule explains body size variation in a diversity of warm-blooded organisms and there is increasing evidence that Bergmann's rule is also widespread in ectotherms. Bergmann's rule acts differentially in species of the Syngnathidae, a family of teleost fishes noted for extreme adaptations for male parental care. While variation in body size of polygamous Syngnathus pipefish is consistent with Bergmann's rule, body size is uncorrelated with latitude in monogamous Hippocampus seahorses. A study of populations of Syngnathus leptorhynchus along a natural latitudinal and thermal gradient indicates that increases in body size with latitude maintain the potential reproductive rate of males despite significant decreases in ambient temperatures. Polygyny is necessary in order to maximize male reproductive success in S. leptorhynchus , suggesting a possible a link between fecundity selection and Bergmann's rule in this species.     

Evolution of female sperm-storage organs in the carrefour of stylommatophoran gastropods

The presence of specialized female sperm-storage organs has been recognized as an important factor influencing postcopulatory sexual selection via sperm competition and cryptic female choice in internally fertilizing species. We morphologically examined the complexity of sperm-storage organs in the carrefour (spermatheca and fertilization pouch) in 47 species of stylommatophoran gastropods. We used partial 28S rDNA sequences to construct a molecular phylogeny, and applied maximum likelihood (ML) and Bayesian methods to investigate the history of spermatheca diversification and to test different hypotheses of sperm-storage organ evolution. The phylogenetic reconstruction supported several gains and losses of spermathecae. Moreover, a complex spermatheca was associated with the occurrence of love darts or other kinds of auxiliary copulatory organs, the presence of a long penial flagellum, and cross-fertilization as the predominant mating system. However, our results also suggest associations of carrefour complexity with body size, reproductive strategy (semelparity versus iteroparity), reproductive mode (oviparity versus ovoviviparity), and habitat type. Carrefour length in 17 snail species possessing a spermatheca was positively correlated with sperm length. Our results indicate that postcopulatory sexual selection as well as life history and habitat specificity may have influenced the evolution of female sperm-storage organs in hermaphroditic gastropods.     

Does a trade‐off between current reproductive success and survival affect the honesty of male signalling in species with male parental care?

Recent theory predicted that male advertisement will reliably signal investment in paternal care in species where offspring survival requires paternal care and males allocate resources between advertisement and care. However, the predicted relationship between care and advertisement depended on the marginal gains from investment in current reproductive traits. Life history theory suggests that these fitness gains are also subject to a trade‐off between current and future reproduction. Here, we investigate whether male signalling remains a reliable indicator of parental care when males allocate resources between current advertisement, paternal care and survival to future reproduction. We find that advertisement is predicted to remain a reliable signal of male care but that advertisement may cease to reliably indicate male quality because low‐quality males are predicted to invest in current reproduction, whereas higher‐quality males are able to invest in both current reproduction and survival to future reproduction.