Larval omnivory in Amara aenea (Coleoptera: Carabidae)

Karel Hůrka,Vojtěch Jarošík

doi:10.14411/eje.2003.052

Abstract

The duration of development, survivorship and adult size were compared for the larvae of Amara aenea reared in the first generation on pure diets of seeds (Stellaria media, Capsella bursa-pastoris, Tussilago farfara, Plantago major, Urtica dioica, or Potentilla argentela), or a pure diet of yellow mealworms (Tenebrio molitor larvae), and on a mixed diet of seeds and mealworm larvae (T. molitor, S. media and C. bursa-pastoris). To ascertain any long-term effects of pure diets, the beetles were reared on the same pure diet for several generations, or on different pure diets in different generations. The hypothesis that the larvae are primary omnivorous was tested. The evidence that the larvae of A. aenea are primary omnivorous was obtained by revealing that the larvae reared on the mixed diet of insects and seeds survived better, and developed faster in larger adults than those reared on the pure diets of seeds or insects. When the beetles were reared on the same pure diet for several generations, survivorship, and in most cases also the duration of development, did not change. However, when the beetles were reared on a different pure diet each generation, survivorship significantly decreased in successive generations.

Highlights

The adults of the genus Amara Bonelli (Coleoptera: Carabidae) are generally considered granivorous, since many have been observed feeding on flower heads or plant-seeds (Kleine, 1912, 1914; Burmeister, 1939; Lindroth, 1945; Burakowski, 1967; Forsythe, 1982; Hůrka, 1996; Luka et al, 1998)
The first con vincing evidence that Amara larvae are granivorous was obtained by Bracht Jorgensen & Toft (1997) that recorded that the lowest mortality of larvae of A. similata occurred when they fed on seeds of Capsella bursa-pastoris
Larvae reared on the mixed diet of Tenebrio molitor, Stellaria media and Capsella bursa-pastoris survived bet ter, and developed faster in larger adults than those reared on the pure diets of seeds of S. media, C. bursa-pastoris, Tussilago farfara, Plantago major and Urtica dioica, or the pure diet of Tenebrio molitor larvae (Table 1, Figure 1)

Summary

Introduction

The adults of the genus Amara Bonelli (Coleoptera: Carabidae) are generally considered granivorous, since many have been observed feeding on flower heads or plant-seeds (Kleine, 1912, 1914; Burmeister, 1939; Lindroth, 1945; Burakowski, 1967; Forsythe, 1982; Hůrka, 1996; Luka et al, 1998). The first con vincing evidence that Amara larvae are granivorous was obtained by Bracht Jorgensen & Toft (1997) that recorded that the lowest mortality of larvae of A. similata occurred when they fed on seeds of Capsella bursa-pastoris. Mor phological features (e.g. broad larval mandibles) sug gest a seed-feeding adaptation (Zetto Brandmayr et al, 1998)

Methods

Results

Conclusion