PLANT&FOREST

Variation in the reproductive rate of Trypoxylus dichotomus (Dymastinae: Sacarabaeidae: Coleoptera) by partition

Won-Jun Seo1,*   Sang-Eun Park2   Young-Nam Youn2,*   

1Department of Agriculture & Life Industry Policy Division, Daejeon Insect Eco Center, Daejeon 35204, Korea
2Department of Agricultural Biology, College of Agriculture and Life Sciences, Chungnam National University, Daejeon 34134, Korea

Abstract

Trypoxylus dichotomus is highly utilized in the domestic insect industry and bred at many farms nationwide. Recently, the number of farmers has been increasing due to the expansion of its use in food and medicine. However, the traditional breeding methods have high economic costs, which include relatively large breeding boxes, large amounts of sawdust and a 2 to 1 ratio (or higher) of female to male. Thus, it is essential to develop a cost-effective breeding method. In this study, a breeding cage with a partition was designed and used to investigate the reproduction rate of T. dichotomus with only a single pair of male and female insect. According to the investigation, the average number of eggs laid in the un-partitioned breeding cage was 93.6, and 121.3 eggs were laid in the partitioned breeding cage. This result shows that T. dichotomus lays more eggs in the partitioned breeding cage rather than in the un-partitioned breeding cage. In addition, it was found that T. dichotomus tends to lay more eggs in compressed sawdust, which was harder than the common fermented sawdust. Through a wind-tunnel assay, it was shown that the ovipositing female recognizes the eggs and avoids them to disperse their eggs elsewhere. These results indicate that the partitioned breeding cage may increase the hardness of the sawdust, restrict the adult’s movement and provide a new place for oviposition for the female, and therefore results in an increased reproduction rate with less cost.

Figures & Tables

Fig. 1. Adult of the dynastid beetle, . (A) Male, (B) female.