Cultivated fruits can serve as an important winter food resource for medium-sized carnivores in rural areas that experience heavy snowfall. However, studies on the food analysis of medium-sized carnivores in heavy snowfall areas, particularly on the use of cultivated fruits, are limited. We evaluated the use of cultivated fruits by medium-sized carnivores during winter in a heavy snowfall area by comparing their feeding habits in rural and forest landscapes. We conducted faecal analysis of Japanese martens (Martes melampus) and red foxes (Vulpes vulpes) in rural and forest landscapes in north-eastern Japan during periods of snow cover. Based on a faecal analysis in the rural landscape, both Japanese martens and red foxes consumed mammals, birds, fruits, and other plant material. In the forest landscape, mammals and insects were consumed by Japanese martens and mammals, fruits, and other plant material were consumed by red foxes. Our results showed that cultivated fruits, such as persimmons and apples, were a major food source in snowy environments, suggesting a wider range of available resources and overlapping feeding habits. It has been suggested that red foxes in forest landscapes move long distances (several kilometres) to consume cultivated fruits. This study suggests that cultivated fruits may also indirectly feed wildlife, even in areas with heavy snowfall.
Research of the physiological traits of a long-distance migratory insect, the common cutworm Spodoptera litura, in relation to flight and reproduction, was focused on triacylglycerol (TG) levels and their fatty acid composition.
Tethered flight experiments demonstrated that three-day old male moths can fly more than 20 h. Among eight identified fatty acids of which the adult TG is composed, the ratios of the following unsaturated fatty acids, palmitoleic acid (C 16:1), oleic acid (C 18:1), linoleic acid (C 18:2) and linolenic acid (C 18:3), gradually declined with longer flight duration. On the other hand, the TG levels of non-flown males reared for ten days on only water, were the same as those of three-day old males after 12 hr of flight, but the ratios of these unsaturated fatty acids in TG's remained nearly unchanged. These results suggest that the unsaturated fatty acids in TG are mainly used as a flight energy source.
As ovarian development in females of this species occurs shortly after adult emergence, long-distance migratory capacity has been regarded as highly unlikely. In fact, ovarian development was completed within three days after adult emergence and females laid eggs thereafter. During this three day period TG increased in the ovary, accompanied by increasing ratios of unsaturated fatty acids in the TG's and the ovary eventually occupied most of the abdomen, in spite of a nearly constant level of TG in the abdomen and unchanged ratio of its unsaturated fatty acids. These facts support the transfer of TG from the fat body to the ovary, and further suggest that the mature females utilize the TG deposited in the ovaries as a flight energy source. Then if they migrate a long distance, they use residual TG after flight for egg production.
Larvae of the stag beetle, Dorcus rectus, feed on decaying wood, which they digest with the aid of symbiotic yeasts; however, they can be successfully reared on artificial diets containing only fungal tissue. In this study we tested whether D. rectus larvae can utilize fungal cell walls, which are an insoluble component of mycelium. Lyophilized Bjerkandera adusta mycelium cultured in potato-dextrose liquid medium consisted of a 47.6% hot-water insoluble fraction by mass, which contains 53.7% of the total nitrogen in the mycelium. D. rectus larvae that hatched from surface-sterilized eggs were reared for 14 days on agar-based diets containing either the soluble fraction, insoluble fraction or both, extracted from 100 mg of mycelium. The larvae increased in mass most on the mixed diet, and there was no difference in their growth on the mixed and positive control diets. Both the soluble and insoluble fractions improved larval growth compared to the negative control diet; however, the growth rates were much lower than those expected from the nitrogen dose-growth response curve obtained in a previous study. Addition of b-chitin to the soluble fraction did not positively affect larval growth. Therefore, we conclude that (1) D. rectus larvae need both the soluble and insoluble fractions of mycelium and (2) the larvae digest the insoluble fraction using their own enzymes., Masahiko Tanahashi, Kôhei Kubota., and Seznam literatury