Studies on May Beetles Injurious to the Turfgrass XIV Effect of Feeding and Mating on Oviposition of Scarab Beetles Injurious to Turfgrass

• Published in: Journal of Japanese Society of Turfgrass Sciense Vol. 10; no. 2; pp. 145 - 154
• Main Authors: HARADA, Junji, YOSHIDA, Masayoshi, HATSUKADE, Masayoshi
• Format: Journal Article
• Language: Japanese
• Published: Japanese society of turfgrass science 15.11.1981
• ISSN: 0285-8800; 1884-4022
• DOI: 10.11275/turfgrass1972.10.145

The object of this study was to determine the effects of feeding and mating on the growth of the ovaries and oviposition of those scarab beetles which multiply only on turfgrass grounds (ex. Anomala osakana Sawada, Anomala schönfeldti Ohaus) and which feed on different types of vegetation as adults and as larvae (ex. Anomala cuprea Hope) . The adults just after emergence were fed turfgrass (Anomala cuprea Hope was fed persimmon leaves.) or reared only with wood flour. They were weighed each day after emergence, and the weight-decrease curves were examined. Weight of ovaries, number of contained eggs and quantity of solid substances were also determined for comparison and examination. 1) All body-weight-decrease curves for male A. osakana, whether given or not given turfgrass and whether reared separately or in pairs, showed similar patterns as in Fig. 2. When females are reared in pairs, whether fed turfgrass or not, the body-weight-decrease curve had a similar tendency to that of males. when a male is reared by itself, whether fed turfgrass or not, the rate of body-weight decrease dropped around nine days after emergence. It is considered that since the adult beetles are reared separately, they did not mate and oviposite. 2) The body-weight-decrease curve of males and females of A. schönfeldti were generally similar to those of A. osakana in every case. 3) When reared without feed, A. cuprea died 10-15 days after emergence in any case, and the weight-decrease curves were generally similar for males and females under the above condition. When fed during rearing, A. cuprea did not ingest food until 7-10 days after emergence and the weight dropped to about 75% of the initial weight. After they began feeding, they maintained a practically constant weight. Since each female of A. cuprea had been reared separately, the females deposited unfertilized eggs starting about 25 days after emergence. Both males and females lived about 40 days. 4) A. osakana and A. schönfeldti showed ovary growth even though they did not ingest food. The ovary weight of both species reached the maximum 6-9 days after emergence. When reared separately, A. osakana and A. schönfeldti kept constant weight after that. When reared in pairs, they lost weight rapidly afterwards. It is thought that this is due to mating and oviposition. A. cuprea did not take food until around nine days after emergence and did not show any ovary-weight increase. When they are fed, however, the ovary weight increased rapidly. 5) In A. osakana and A. schönfeldti, a similar tendency is observed between variations of the number of contained eggs and the ovary weight. 6) Adult A. osakana and A. schönfeldti are assumed to copulate without fail within the rearing cage, if they are reared in pairs.