Biology of Holotrichia longipennis and Holotrichia sikkimensis (Coleoptera: Scarabaeidae) in north-western Himalaya, India and morphological description of their immature stages

The biology of Holotrichia longipennis and Holotrichia sikkimensis was studied in north western Himalaya and their immature stages were described. The average length × width of newly laid eggs of H. longipennis and H. sikkimensis was 1.41 × 1.10 mm and 2.16 × 1.18 mm, and the eggs hatched in 14 and 16.20 days, respectively. There were three larval instars. The larvae of H. longipennis measured 10.22, 23.48 and 36.59 mm in the I-III instars, respectively. Head capsule width was 1.74, 3.48 and 5.06 mm in the I-III instars, respectively. Body lengths attained by larvae of H. sikkimensis were 11.53, 24.86 and 36.12 mm for I-III instars, respectively. The respective head capsule widths were 1.82, 3.98 and 5.15 mm. Duration of the first two instars was 36.0 and 35.06 days in H. longipennis , and 29.40 and 36.93 days in H. sikkimensis . The third instar was the overwintering stage occupying 204.75 days in H. longipennis and 200.76 days in H. sikkimensis . The duration of the total larval period was 275.81 and 266.09 days for H. longipennis and H. sikkimensis , respectively. A detailed comparative description of the mouth parts, raster, spiracles of larvae and caudal appendages of pupae is given with the help of suitable microscopic pictures and line diagrams. The larvae of these species can easily be distinguished based on mandibles, epipharynx and raster pattern.