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Mating Status (mating + status)
Selected AbstractsFunctional morphology of the postpharyngeal gland of queens and workers of the ant Monomorium pharaonis (L.)ACTA ZOOLOGICA, Issue 2 2006Dieter Eelen Abstract Eelen D., Børgesen L.W. and Billen J. 2006. Functional morphology of the postpharyngeal gland of queens and workers of the ant Monomorium pharaonis (L.). ,Acta Zoologica (Stockholm) 87: 101,111 The postpharyngeal gland (PPG) is unique to ants and is the largest exocrine gland in their head. In queens of the pharaoh's ant, Monomorium pharaonis, the gland contains approximately 15 finger-like epithelial extensions on each side and opens dorsolaterally in the posterior pharynx. In these ants the PPG morphology varies considerably according to age and mating status. The epithelial thickness increases with age and reaches a maximum at 3 weeks in both virgin and mated queens. A considerable expansion of the lumen diameter occurs in both groups between 4 and 7 days. Virgin queens release their secretion into the gland lumen from an age of 7 days, whereas mated queens accumulate large amounts of secretion in their epithelium. The increasing epithelial thickness, together with the increasing lumen diameter, the presence of numerous inclusions in the epithelium and the release of secretion, are indicative for increasing gland activity. The gland ultrastructure indicates involvement in lipid metabolism and de novo synthesis of lipids. The PPG of workers consists of 12 finger-like tubes at each side. There is a significant difference in epithelial thickness between nurses and repletes and between nurses and foragers. We suggest the PPG serves different purposes in pharaoh's ants: it is likely that the PPG of workers and virgin queens is used to feed larvae. In mated queens the gland probably plays a role in providing the queen with nutritious oils for egg production. The PPG may also function in signalling species nestmate and caste identity, as well as in the reproductive capacity of the queens. [source] Male Mate Choice in the Guppy (Poecilia reticulata): Do Males Prefer Larger Females as Mates?ETHOLOGY, Issue 2 2004Emily J. E. Herdman Although females are the choosier sex in most species, male mate choice is expected to occur under certain conditions. Theoretically, males should prefer larger females as mates in species where female fecundity increases with body size. However, any fecundity-related benefits accruing to a male that has mated with a large female may be offset by an associated fitness cost of shared paternity if large females are more likely to be multiply mated than smaller females in nature. We tested the above hypothesis and assumption using the Trinidadian guppy (Poecilia reticulata) by behaviourally testing for male mate choice in the laboratory and by ascertaining (with the use of microsatellite DNA genotyping) patterns of male paternity in wild-caught females. We observed significant positive relationships between female body length and fecundity (brood size) and between body length and level of multiple paternity in the broods of females collected in the Quaré River, Trinidad. In laboratory tests, a preference for the larger of two simultaneously-presented virgin females was clearly expressed only when males were exposed to the full range of natural stimuli from the females, but not when they were limited to visual stimuli alone. However, as suggested by our multiple paternity data, males that choose to mate with large females may incur a larger potential cost of sperm competition and shared paternity compared with males that mate with smaller females on average. Our results thus suggest that male guppies originating from the Quaré River possess mating preferences for relatively large females, but that such preferences are expressed only when males can accurately assess the mating status of encountered females that differ in body size. [source] Fluctuating Asymmetry, Sexual Selection, and Survivorship in Male Dark-Winged DamselfliesETHOLOGY, Issue 9 2002Michelle L. Beck We examined fluctuating asymmetry and morphology as they relate to reproductive success, territoriality, and relative survivorship in the dark-winged damselfly Calopteryx maculata. Fluctuating asymmetry was not correlated with any aspect of morphology in males, but it did predict mating status in males. Mating males showed significantly lower levels of forewing asymmetry than did non-mating males holding adjacent territories. While fluctuating asymmetry did not relate to survivorship or resource holding ability, body size did. Larger males were able to hold territories longer and lived longer than smaller individuals. We suggest that size is of greater importance in this species with regards to fitness and that fluctuating asymmetry may play a minor role by impacting short-term mating success. [source] Reproductive asynchrony in natural butterfly populations and its consequences for female matelessnessJOURNAL OF ANIMAL ECOLOGY, Issue 4 2008Justin M. Calabrese Summary 1Reproductive asynchrony, where individuals in a population are short-lived relative to the population-level reproductive period, has been identified recently as a theoretical mechanism of the Allee effect that could operate in diverse plant and insect species. The degree to which this effect impinges on the growth potential of natural populations is not yet well understood. 2Building on previous models of reproductive timing, we develop a general framework that allows a detailed, quantitative examination of the reproductive potential lost to asynchrony in small natural populations. 3Our framework includes a range of biologically plausible submodels that allow details of mating biology of different species to be incorporated into the basic reproductive timing model. 4We tailor the parameter estimation methods of the full model (basic model plus mating biology submodels) to take full advantage of data from detailed field studies of two species of Parnassius butterflies whose mating status may be assessed easily in the field. 5We demonstrate that for both species, a substantial portion of the female population (6·5,18·6%) is expected to die unmated. These analyses provide the first direct, quantitative evidence of female reproductive failure due to asynchrony in small natural populations, and suggest that reproductive asynchrony exerts a strong and largely unappreciated influence on the population dynamics of these butterflies and other species with similarly asynchronous reproductive phenology. [source] Quantification and ultrastructure of oosorption in Eretmocerus eremicus (Hymenoptera: Aphelinidae)JOURNAL OF MORPHOLOGY, Issue 9 2006Mark K. Asplen Abstract The potential for and ultrastructure of oosorption were examined in Eretmocerus eremicus, a short-lived whitefly parasitoid that obligately produces anhydropic oocytes. In the absence of hosts, median egg load decreased by ,12% per day between 2 days and 8 days following eclosion. Parasitoid mating status had no significant effect on either egg load alone or the relationship between egg load and age. Yolk degradation in E. eremicus is autolytic, with the enzymes required for yolk sphere digestion apparently being derived from within the ooplasm. The exochorion appear to be digested by the follicular epithelium concurrent with the uniform degradation of the entire ooplasm. The potential adaptive benefits of this novel oosorption mechanism to E. eremicus females include a reduction in the total digestion time per oocyte and resorption of chorion remnants. Finally, to our knowledge, the results of this study provide the first unequivocal ultrastructural evidence of a purely autolytic oosorption mechanism in Insecta. J. Morphol. © 2006 Wiley-Liss, Inc. [source] | ||||||||||