The ontogeny of kin recognition in tadpoles of the toadBufo melanostictus (Anura; Bufonidae)

The ontogeny of kin recognition and influence of social environment on the development of kin recognition behaviour was experimentally investigated in tadpoles of Bufo melanostictus that lived in aggregations and showed low larval dispersion. Embryos and tadpoles of the toad were reared as (i) kin only, (ii) with kin and non-kin (separated by a mesh screen), and (iii) in isolation. They were tested for the ability to discriminate between (i) familiar siblings and unfamiliar non-siblings, (ii) familiar siblings and familiar non-siblings and, (iii) unfamiliar siblings and unfamiliar non-siblings. All tadpoles were fed on boiled spinach before conducting trials. Preference of test tadpoles to associate near the end compartments whether empty or containing members of specific stimulus groups was assessed using a rectangular choice tank. When tested in tanks with empty end compartments, the test tadpoles showed random distribution and thus no bias for the apparatus or the procedure. In the presence of kin/non-kin in the end compartments a significantly greater number of test tadpoles spent the majority of the time near familiar or unfamiliar kin rather than near familiar or unfamiliar non-kin. Kin discrimination ability persisted throughout larval development. Familiarity with siblings is not required for discriminating kin from non-kin, and kin discrimination ability is not modified following exposure to non-kin. Also, involvement of dietary cues is unlikely to be the prime mechanism of kin recognition inB. melanostictus unlike in some other anurans

Members of opposite sex mutually regulate gonadal recrudescence in the lizard Calotes versicolor (Agamidae)

Adult males and females of the seasonally breeding lizard Calotes versicolor were subjected to various social situations under semi-natural conditions to explain the role of socio-sexual factors in gonadal recrudescence. They were grouped as: (i) males and females, (ii) males and females separated by a wire mesh, (iii) same sex groups of males or females, (iv) castrated males with intact females and (v) ovariectomized (OvX) females with intact males from postbreeding to breeding phase. Specimens collected from the wild during breeding season served as the control group. Plasma sex steroid levels (testosterone in male and 17β-estradiol in female), spermatogenetic activity and vitellogenesis were the criteria to judge gonadal recrudescence. In intact males and females that were kept together, gonadal recrudescence and plasma sex steroids levels were comparable to those in wild-caught individuals. Gonadal recrudescence was at its least in all male and all female groups, and plasma sex steroids were at basal levels. Association with OvX females initiated testicular recrudescence but spermatogenetic activity progressed only up to the spermatid stage while males separated from females by wire mesh showed spermatogenetic activity for a shorter period. Females grouped with castrated males and those separated from males by wire mesh produced vitellogenic follicles. However, the total number and diameter of vitellogenic follicles, and plasma estradiol levels were lower than in the females grouped with intact males. The findings indicate that association with members of the opposite sex with progressively rising titers of sex steroids is crucial in both initiating and sustaining gonadal recrudescence in the lizard. Thus, members of the opposite sex mutually regulate gonadal recrudescence in the C. versicolor

Mating and nesting behaviour, and early development in the tree frog Polypedates maculatus

While the male of the tree frog, Polypedates maculatus, in axillary amplexus with female (l.e, with its vent closer to that of the female) constructs terrestrial foam nest by whipping up the released seminal fluid with its hind limbs, the female releases eggs (210 448) that are unpigmented. The duration of this process is about 2.5 h. The eggs complete their embryonic development in the foam nest within nine days, and the Iarvae complete their metamorphosis in 60 ± 10 days

Effect of thiourea on human chorionic gonadotrophin (hCG) induced spermatogenesis in the frog Rana Tigerina during the postbreeding regression phase

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Description of tadpose Rana temporalis from South India

The paper describes morphology and morphometry (total length, snout-vent length, internaral, inter- orbital, snout-naral distances etc.) of Rana temporalis tadpoles found in gently-flowing and still water bodies along the streams in the south-western ghats. The mouth is ventral, oral disc is large, teeth are blunt and devoid of cusps. The tadpoles are muddy green yellowish. In these tadpoles, the spiracle is single, sinistral and adnate with the body. The tail musculature is moderately developed. The dental formula is 2(2)/3(1). There are 2-3 rows of labial papillae. The oral features are well suited for grazing at the substratum, and to adhere to rocks against gentle water currents