Anxiousness, Self-esteem, and Anxiety: Which Variable is a Predictor?

The paper deals with the issue on the relations of self-esteem, anxiousness and anxiety at teenagers. The aim of the research was to identify the influence of anxiousness on self-esteem and influence of self-esteem on anxiety within a sample of adolescents and intersexual difference in variables. The research sample consisted of 2 374 adolescents (females n = 1149) out of which 356 suffer from the symptoms of anxiety disorders (ADS; females n= 263). The variables were gained through the revised Rosenberg self-esteem scale and SUDS scales for anxiousness and anxiety findings. Using statistical analyses it was found that females reached a lower average score in self-esteem (t = 10.512; p <.001) and a higher average score in anxiousness (t = 10.132; p <.001). Similar results were achieved also at the sample of adolescents in variables of self-esteem (t = 3.611; p <.001) and anxiety (t = 5.845; p <.001). Furthermore, was found that there is a statistically significant predictable relation between research variables: anxiousness is a predictor of self-esteem (F = 2495.490, p<.001) at a non-ADS sample of respondents, whereby ADS respondents´ self-esteem is a significant predictor of anxiety (F = 83.810, p<.001).

Flowering phenology and mimicry of the rattan Calamus castaneus (Arecaceae) in southern Thailand

In the insect-pollinated dioecious rattan Calamus castaneus Griff., nectar and pollen rewards, together with visual and olfactory cues, attract insects to male flowers. Pistillate flowers are apparently rewardless. Here, we aimed to clarify the mechanisms assuring visitation and pollination of female flowers. We studied features of flowering phenology and floral biology that affect pollination success of plants of both sexes. The results show that C. castaneus features a striking system of mimicry, quite different from those studied previously in other dioecious plants. The population of C. castaneus was not significantly male biased and no intersexual difference in number of inflorescences per plant was detected. However, male plants began their blossoming earlier and flowered longer than female plants. There was thus an excess of male floral display. This excess should increase the frequency of insect-mediated transport of pollen from male to female plants. Furthermore, on female plants each pistillate flower is accompanied by a sterile staminate flower that appears to contribute to insect attraction. Quite similar in morphology and function to fertile staminate flowers, they produce similar visual and olfactory cues, but less rewards (nectar but no pollen). C. castaneus thus ensures pollination success by intersexual phenological differences and by floral mimicry.

Evolution of sexual dimorphism in the forelimb muscles of Andrew's toad (Bufo andrewsi) in response to putative sexual selection

Sexual differences in morphological traits are widespread among animals. Theory predicts that dimorphism in secondary sexual characters evolves as a consequence of sexual selection. We investigated the intersexual difference in mass of forelimb muscles of the Andrew's toad, Bufo andrewsi, an elongated species inhabiting montane regions in western China. Our results showed that average body size of females was significantly larger than males. However, when the influence of body size was removed, the forelimb muscle mass of males significantly exceeded that of females, and total mass of forelimb muscles of amplectant males was significantly larger than that of non-amplectant males. These results suggest that the robustness of the forelimbs can allow amplectant males to retain a firm grip on the female in amplexus, which may aid resistance to inference by conspecific males. Our findings are consistent with the prediction that sexual selection favors large forelimb muscle mass in males.

Are endemic snakes with a narrow distribution more specialist than their wide-ranging counterparts? Evidence from the prey composition and morphometric correlates of the diet in Zamenis lineatus, a rat snake endemic to southern Italy

The snakes of the Mediterranean regions are in general characterised as wide ranging with relatively unspecialised ecological traits (e.g., feeding ecology and diet composition). The few endemic snake species with a narrow range can be of great interest to control whether the relative ecological non-specialization is truly general for Mediterranean snakes or if, on the contrary, those species with a small range are so because of their more specialised ecology. Here, we study the case of the Italian Aesulapian snake, Zamenis lineatus, which is endemic to southern Italy and the island of Sicily, and that has been for long time considered merely as a subspecies of the widespread Zamenis longissimus. We studied the diet of this species in the wild, and also examined snout-vent length and head length in several museum vouchers in order to highlight the eventual morphometric correlates of diet composition. Our results showed (i) a diet based on small mammals and birds, (ii) an evident ontogenetic shift in diet composition (from ectotherms to endotherms), and (iii) a lack of significant intersexual difference in diet composition. In addition, morphometric data revealed no intersexual differences in average snout-vent-length or head length. The general implications of these results are discussed. We conclude that, based on this study case, Zamenis lineatus feeding ecology was very similar to that of the widespread and ecological generalist Zamenis longissimus, and this is contrary to the hypothesis that endemic, narrowly distributed Mediterranean snakes may be more specialist than their widespread counterparts.

Assessment of age and intersexual size differences in Bufo bufo

Numerous studies have underlined the complex nature of relationship between age, size, and reproductive traits in anurans. One of the most intriguing problems for evolutionary biologists is intersexual difference in body size (SSD). For testing various hypotheses about SSD, we need reliable estimates of its extent (the important issue being the choice of trait for analysis) as well as the accurate determination of individual age. The measures of SSD may be subject to error if estimated from populations with unknown age distribution; amphibians continue to grow throughout their life and SSD is linked to sex differences in traits such as age at maturity and lifespan. In the present paper, we analyze problems involved in accurate determination of age structure and factors that may lead to under- or overestimation of individual age, as well as the problem of appropriate choice of traits, in the light of our experience and results of investigating populations of common toad (Bufo bufo) in the vicinity of Belgrade.

Body size, diet and reproductive ecology of Coluber hippocrepis in the Rif (Northern Morocco)

Although it is generally assumed that the Horseshoe Whip Snake (Coluber hippocrepis) originated in northern Africa, its biology and ecology has been studied mainly in southern Europe. In this paper we report on morphology, feeding, and reproductive ecology of Coluber hippocrepis in the Rif region (northern Morocco). Males attained larger sizes than did females, but there was no body-size difference between populations separated by the Strait of Gibraltar. The species feeds exclusively on vertebrates: mammals (45%), reptiles (28%), birds (17%), and amphibians (10%). There was an ontogenetic dietary shift in terms of frequency of prey consumed and in terms of prey size; moreover, an intersexual difference in prey frequency was found. Sexual maturity was attained at 540 mm snout-vent length (SVL) in males, and 720 mm SVL in females. Males showed a vernal spermatogenic cycle. Oviposition occurred at the beginning of summer, and offspring were observed in the field during September.

Intersexual Transfer of a Toxic Terpenoid during Copulation and Its Paternal Allocation to Developmental Stages: Quantification of Cantharidin in Cantharidin-Producing Oedemerids (Coleoptera: Oedemeridae) and Canthariphilous Pyrochroids (Coleoptera: Pyrochroidae)

In whole body extracts of the canthariphilous pyrochroid Schizotus pectinicornis and the cantharidin-producing oedemerid Oedemera femorata cantharidin contents were determined by means of quantitative gas chromatography. Adults and all developmental stages of both species contain this terpenoid, but in considerably different amounts. Cantharidin contents differ significantly between the sexes of adult O. femorata: 8.4 μ,g/female, 3.5 μg/male. Values for Sch. pectinicornis are more than 30-fold lower than those of O. femorata and no intersexual difference in the cantharidin content could be detected. Eggs of O. femorata contained cantharidin and larvae of this species are capable of synthesizing this terpenoid. The total amount of cantharidin increases in successive instars. In Sch. pectinicornis, the content of cantharidin decreases from egg to first instar.Feeding and copulation experiments with [2H2]cantharidin indicate that in O. femorata no or only very small amounts of cantharidin are transferred from males to females at copulation. Thus, males do not invest in the protection of their offspring by cantharidin gifts to the mate. For Sch. pectinicornis an intersexual transfer of labelled cantharidin during copulation was detected. About 45% of the entire cantharidin content in mated females derived from fed males. Analyses of eggs and first instar larvae show that a paternal allocation of 2[H2]cantharidin to developmental stages exists for this canthariphilous pyrochroid.

Intersexual differences in growth, mortality, and size at maturity in bullfrogs in central Ontario

A population of bullfrogs (Rana catesbeiana) in Algonquin Provincial Park, Ontario, Canada, was studied from May 1985 through October 1987. Of 1187 individuals marked with tattoos, 567 were recaptured at least once. The age of each marked individual was estimated using size–frequency distributions. A negative relationship between age and sex ratio indicated lower survivorship for mature males than for mature females. The average age at maturity was estimated to be 5 years post-transformation (YPT), at 113 mm standard length (snout to urostyle) for females, and 3 YPT, at 91 mm, for males. The minimum age at maturity was 4 YPT, at 94 mm standard length, for females, and 3 YPT, at 90 mm, for males. Age at maturity was greater, and size at maturity smaller, than reported for other populations. A logistic growth model fitted to the data, and comparison of age-specific mean standard lengths, indicate an intersexual difference in the pattern of growth. The asymptotic maximum standard length, as derived from the logistic model, was 181 mm for females and 148 mm for males. The estimated growth constant, r, was greater for males than for females, indicating that males attained their maximum size at a younger age than did females.