Genetic Determinacy of the Behavioral Activity of the Silkworm (Bomby xmori L)

Тhe behavioral activity of such an extremely important agricultural object in scientific and practical terms as the silkworm still remains poorly studied. Aims: Сreation of silkworm lines with alternative behaviors to prove the genetic determinacy of the behavioral activity of the silkworm Bombyx mori L. Place and Duration of Study: The work was carried out at the Research Institute of Sericulture in the Laboratory of Genetics and Breeding of the silkworm in 2015-2020. The Ipakchi 1 and Ipakchi 2 breeds widely zoned in Uzbekistan were used as research objects. Methodology and Results: The Ipakchi 1 and Ipakchi 2 breeds widely zoned in Uzbekistan were used as research objects. The breeding of alternative silkworm lines in terms of motor activity was carried out by selecting the most active caterpillars and male butterflies in the "A" -lines (active), and the least active individuals in the "P"-lines (passive). The separation of individuals by motor activity led to their separation by reproductive and biological indicators. The difference between the lines by the average number of eggs in the clutch of the Ipakchi 1 breed in 2018 was 32 eggs, in 2020 already 133 eggs; by the mass of the clutch in 2018 – 25mg, in 2020 – 78mg. The same patterns were observed in the Ipakchi 2 breed. The greatest difference between the "A" and "P" lines was observed in the viability of caterpillars: in 2018 it was 3.2%, in 2020 already 6.9%. Conclusions: Selection of hatched larvae (caterpillars) and male butterflies by the speed of movement to the feed (the larvae) and to the sexual partner (butterflies) leads to the appearance of silkworm lines with alternative forms of motor activity.

Anti-aphrodisiac pheromone, a renewable signal in adult butterflies

The male butterfly Pieris napi produces the anti-aphrodisiac pheromone methyl salicylate (MeS) and transfers it to the female during mating. After mating she releases MeS, when courted by conspecific males, which decreases her attractiveness and the duration of male harassment, thus increasing her time available for egg-laying. In previous studies we have shown that males produced MeS from the amino acid L-phenylalanine (L-Phe) acquired during larval stage. In this study we show that adult males of P. napi can utilize L-Phe and aromatic flower volatiles as building blocks for production of anti-aphrodisiac pheromone and transfer it to females during mating. We demonstrate this by feeding butterflies with stable isotope labelled molecules mixed in sugar solutions, and, to mimic the natural conditions, we fed male butterflies with floral nectar of Bunias orientalis plants treated with labelled L-Phe. The volatiles from butterflies and plants were collected and identified by solid phase micro extraction, gas chromatography and mass spectrometry techniques. Since P. napi is polygamous, males would gain from restoring the titre of MeS after mating and the use of aromatic precursors for production of MeS could be considered as an advantageous trait which could enable butterflies to relocate L-Phe for other needs.

Field and Laboratory Studies on the Ecology, Reproduction, and Adult Diapause of the Asian Comma Butterfly, Polygonia c-aureum L. (Lepidoptera: Nymphalidae)

Adult diapause and reproduction of a nymphalid butterfly, Polygonia c-aureum L., were investigated in field and laboratory examinations. Laboratory studies showed that old virgin male butterflies of non-diapausing generations had heavy accessory glands and simplex, which were suppressed in diapausing generations. The number of eupyrene sperm bundles in the duplex increased with adult age, whereas testis size decreased with age. Field examinations indicated that reproductive development of both sexes of diapausing generations in autumn was suppressed, and developed in spring. We attempted to estimate the physiological age of wild-caught males, as adult male age can be estimated from the testis size. We also attempted to determine whether or not wild male butterflies had mated from the development of the accessory glands and simplex, as well as the number of eupyrene sperm bundles in the duplex, by comparing unmated males with mated males. Field examinations suggest that almost all females in a population of non-diapausing generations mated and showed a tendency toward polyandry, while in the diapausing generation, in spring, monoandry rather than polyandry predominated. This suggests a different mating strategy between non-diapausing and diapausing generations.