Morphological description of the house cricket (Acheta domesticus Linnaeus, 1758; Orthoptera: Gryllidae) egg in captivity

Abstract

The house cricket (Acheta domesticus) is a nutrient-rich insect that can be mass-produced for food to bridge the nutritional gap of human food. Good knowledge of the different developmental stages is crucial for the success of its farming. This study is therefore aimed at understanding the morphological changes of house cricket egg, first stage of the development cycle, but unfortunately little studied. To achieve this, 92 eggs were observed, measured and described in the laboratory. Measurements were taken from day one old to hatching. Six days after oviposition, the outer chorion degradation had started. From ten days, the translucent chorion was visible, revealing the eyes of the embryo as well as bilateral symmetry. An advanced pigmentation, metamerism and the presence of cerci were then observed on day twelve (12). The incubation time for this elongated egg was sixteen (16) days. During this period, variations in egg length (2.53 ± 0.10 mm to 3.32 ± 0.24 mm) and width (0.75 ± 0 mm to 0.99 ± 0.04 mm) were recorded. As for the volume, a variation of 0.66 ± 0.03 mm3 to 1.92 ± 0.23 mm3 was noted. Egg length, width and volume increased slowly from 1 to 4 days. This increase was somewhat faster from 4 to 8 days before reaching a plateau until hatching. A variation in the egg aspect ratio from 3.38 ± 0.14 to 3.36 ± 0.24 was then noted throughout development. The results of the present study could form a basis for successful breeding of this insect.