Estimation of the retention times and distances of seed dispersed by two monkey species, Alouatta seniculus and Lagothrix lagotricha, in a Colombian forest

Isolated-bout method to estimate the retention times and dispersal distances was applied to the seed dispersal by red howler monkeys (Alouatta seniculus) and Humboldts woolly monkeys (Lagothrix lagotricha) in a lowland tropical forest at La Macarena, on the border of the Macarena and Tinigua National Parks, the Department of Meta, Colombia. Continuous observations were made on the feeding and ranging behavior of well-habituated troops of howler monkeys and woolly monkeys as well as continuous collection of monkeys feces. We selected out the isolated-bout as a feeding bout on the specific species that was only once recorded within 48 h before the seeds of that species appeared in the feces of monkeys. In that case, the seeds were strongly suggested to come from that isolated bout. Then retention times, route seed dispersal distances and direct seed dispersal distances were estimated. Howler monkeys, which are regarded as generalist herbivores, showed longer retention times and dispersal distances along monkeys route than did woolly monkeys, which are specialist frugivores. However, the direct distances that seeds were carried from the mother tree were not significantly greater for howler monkeys than for woolly monkeys. This shows that both retention time and movement patterns by the monkeys, especially the total ranging area, influence the direct distance that seeds are carried from the mother tree.     

Reproductive Parameters of Wild Female Lagothrix lagotricha

I describe the reproductive patterns of female woolly monkeys (Lagothrix lagotricha) based on a 12-year study of one group of them at Macarena Ecological Investigations Center, Meta, Colombia. As in other atelin species—muriquis and spider monkeys—characterized by male philopatry, female woolly monkeys leave their natal groups. The age of emigration is ca. 6 years. Females probably begin to copulate with adult males soon after emigration, while their mean age of first parturition is 9 years. They frequently changed groups until they birthed. The average interbirth interval is 36.7 mo (n = 13). All births occurred between July and December (late wet season to early dry season). Copulation occurred throughout the year. However, they copulated more frequently in the estimated conception period from December to May (early dry season to early wet season) than in the birth season. The females had a period of sexual inactivity averaging <23.4 mo after parturition, followed by a period of sexual activity >7.2 mo until conception. The copulation period and copulation cycle or interval between copulation periods averaged 2.3 and 11.3 days calculated by a conventional method, or 3.1 and 14.7 days by a slightly modified method. The reproductive parameters of woolly monkeys are quite similar to those reported for other atelins in many respects, except the immigration process and age of first copulation.     

A marking-and-recapture analysis of the adult population of a phytophagous lady-beetle,Epilachna sparsa orientalis

A marking-and-recapture study of a population of overwintered adults of Epilachna sparsa orientalis was carried out in a small farm containing potatoes and egg-plants. The experiment involved a single release and five recapture samplings during May–June. The data were analysed byLeslie's re-recapture method. Assumption of randomness of sampling proved to be well satisfied. Survival rate of the overwintered adult population was maintained as high as 90 per cent per week or more until early June, and then it declined rapidly towards the end of June. Initially overwintered adults exclusively lived on potato plants, but half of the population alive in mid June migrated to nearby egg-plants. Emigration out of the experimental field, however, seemed not to be occurring. Recapture data of marked individuals in the potato field indicate that majority of the individuals stayed within a radius of 3 m, at least for 2 weeks. Similar data taken from another field also suggest that their mobility was far restricted as compared with random movement within the field. Some comparisons were made between the population behaviours of overwintered adults of E. sparsa orientalis and E. vigintioctomaculata.     

Spore germination and phytochrome biosynthesis in the fern Lygodium japonicum as affected by gabaculine and cycloheximide

We investigated whether the gradual increase in phytochrome content in the fern Lygodium japonicum (Thunb.) Sw. during dark imbibition results from hydration or from biosynthesis of phytochrome. Addition of gabaculine or cycloheximide to the culture medium caused inhibitions of both red light-induced spore germination and of the appearance of phytochrome in the spores. Fifty percent inhibition of both red light-induced germination and of the appearance of phytochrome in the spores occurred at ca 10⁻7 M cycloheximide. Red light-induced germination and phytochrome appearance were markedly inhibited by 10⁻4 M and completely by 10⁻3 M gabaculine, but germination induced by gibberellic acid was unaffected. Phytochrome was not detected in spores after forced hydration. These results suggest that the increase in phytochrome during imbibition was mainly due to de novo synthesis of the phytochrome apoprotein and to synthesis of the chromophore and/or proteins required for phytochrome formation, rather than to hydration of preexisting phytochrome molecules.