Authors: M. B. H. Moha Mmed

Authors: Brian Banks And Trevor J. C. Beebee

Authors: J. L. Cloudsley-thompson

Authors: E. Hailey, E. A. Rose and E. Pulford

Abstract: Chalcides bedriagai were found to live under rocks, mostly at body temperatures between 25-35°C, and were active between mid-March and mid-October. Population density (excluding juveniles) was 42 Ha-I in an abandoned field habitat, 990 Ha-1 in the utilised sub-habitat. Larger females had more young (overall range 1-6 per year), but offspring size and relative clutch mass (mean 0.37) were independent of maternal size. Escape success was linearly related to substrate temperature (T5), ranging from 0 at l 7°C to 0.5 at 37°C. Pregnant females were found under rocks with higher T5 than other adults, and had reduced food intake. Food consumption of adults in summer was estimated from the production of urates as 12mg dry weight.g live weight-I .day-1. This is similar to that of a cool temperate lacertid and a tropical nocturnal gecko, but only half that of a warm temperate lacertid. Energy expenditure on hibernation, maintenance and activity was estimated from the annual temperature profile and values of metabolic rate. Estimates were also made for energy used in reproduction, growth and sloughed skins. The total annual budget suggested an average daily food intake only half of that estimated in summer, and half of that expected from a general relation for active lizards in warm climates.

Authors: J. D. Harrison

Abstract: The guts of frog tadpoles in Llysdinam Pond, 1 983, frequently contained detritus (partially decomposed macrophyte tissue) and other items associated with the pond's sediment (the tests of rhizopod protozoa, pollen grains, fungi), suggesting that the frog tadpoles fed directly on the sediment. The guts of toad tadpoles from Llysdinam, 1 984, however, contained high frequencies of rotifers (Keratella) and motile algae (Dinophyceae) and little detritus, suggesting that the toad tadpoles fed mainly in m id-water. Evidence of both m id-water and sediment feeding was observed in samples of toad tadpoles from other ponds. Samples of frog tadpoles from other ponds, however, showed only the sediment feeding mode.

Authors: R. Meek

Abstract: Field observations have been made on a North African population of Mauremys caspica leprosa. Measurements on 73 animals has provided information on population structure and morphometrics. In a sample of 67 terrapins measured in September carapace lengths ranged from 22- 1 86mm although the majority (59.7 percent) were below 80mm. Body masses ranged from 4-906g but most animals (? 1 .6 per cent) were below IOOg. Females grow larger than and outnumbered males by 2. 1 2: I, terrapins above one year outnumbered hatchlings by 4. 1 5: I. Equations have been produced relating growth annuli (age) to carapace length. These indicate that females grow faster than males but that males outlive females. A general equation predicts that large animals (>200mm C. length) may attain at least 26 years in field populations. Younger animals predominated in the population and 68. l per cent were aged less than seven years. Equations defining the relationship between body mass and the principal dimensions of the shell have indicated sexual d imorphic trends in shell morphometry during growth . M. caspica were found with leeches, shell damage and algal growth on the carapace.

Authors: Paul A. Verrell

Abstract: Growth during the aquatic phase of the annual cycle (measured as change in snout-vent length) was investigated in a natural population of smooth newts (Triturus vu!garis) at a pond in southern England in 1 983. Two types of data were collected: growth at the population level (quantified as changes in mean snout-vent length) and growth in individual, recaptured newts. For the population as a whole, significant growth was detected during the aquatic phase. At the level of individual newts, rate of growth during this period was negatively correlated with snout-vent length at entry to the pond; such a relationship is common in the Amphibia. The average growth rate of adult newts observed during the present field study (1.1-1.5mm) agrees closely with an independent estimate (about 1.5mm) obtained during a previous, skeletochronological investigation (Verrell and Francillon, 1986).

Authors: Neelima B. Chauhan

Abstract: The influence of exogenous testosterone on the epidermal glands i.e. ß-glands and pre-a nal glands, of Hemidactylus jlaviviridis was studied 15 and 30 days post treatment during breeding and non-breeding phases of gonadal cycle. Parameters l ike length and breadth of pre-anal glands and their cellular and nuclear dimensions, appearance of further development of ß-glands were considered. In general , it was found that the changes observed 30 days post treatment were more obvious, however, 15 days of treatment did influence both the glands studied, to some extent. Also the exogenous hormone showed pronounced effect during non-breeding period than during the breeding period.

Authors: William H. N. Gutzke

Abstract: Sex determination and sexual differentiation in vertebrates have received a great deal of attention in the past few decades. The current view is that gonochorism (separate sexes) in the earliest vertebrates involved environmental control of sex determination and that genotypic sex determination evolved later (lntersexuality in the Animal Kingdom, 438, 1 975). Concurrent with the establishment of the latter was the gradual evolution of sex chromosome heteromorphism. Reptiles are excellent models for investigations focusing on sex determination' and sexual differentiation because they exhibit: (a) both genotypic and environmentally-determined sex determination, (b) various degrees of sex chromosome heteromorphism, ( c) both male and female heterogamety (the former also occurs in mammals, the latter in birds), and (d) variations from the typical I: 1 sex ratio predicted by Fisher (The Genetical Theory of Natural Selection, 1 930). This paper will review patterns of sex determination for the various groups of reptiles and will briefly discuss physiological mechanisms that may be regulating sexual differentiation.