Chapter 9 Sampling, Conserving and Identifying Fruit Flies Neliton Marques da Silva INTRODUCTION Among the fruit pests of tropical America, the fruit flies are considered of greatest economic importance, as they are key-pests for most of the fruit crops. They are multi- voltine insects with relatively high biotic potential, and great capacity to infest different native and exotic fruit species. They belong to the order Diptera, family Tephritidae. Five genera are important as pests: Anastrepha, Bactrocera, Ceratitis, Rhagoletis and Dacus, which are spread globally throughout the continents, except Antarctica (White and Elson-Harris, 1992). A few studies have highlighted the ecology and aetiological aspects of fruit flies, mainly focusing on the pupal and larval phases (Silva et al, 1996; Zucchi et al, 1996). Fruit flies have complex behaviour and taxonomy (Bateman, 1972; Steck and Wharton, 1988). Classification is exclusively based on adult morphological characteristics. The sexes are easily distinguished, as females have an ovipositor quite prominent at the end of the abdomen, with a long and fine tip. Taxonomic characteris- tics differentiating gender in larvae and pupae are not yet established (Salles, 2000). Damage is caused during the immature phase, a period in which the larvae destroy the fruit pulp, making them unsuitable for harvesting and consumption. Before they reach the adult stage, the larvae migrate from the fruit to pupate in the soil (Plate 8a). Thus, fruit flies are temporary soil inhabitants, because they live only part of their life cycle in soil. After infested fruits have dropped, larvae move on the soil surface to find suitable soil conditions, penetrate to approximate 10cm depth and pupate. This depth can vary accord- ing to physical soil conditions, mainly temperature, humidity and texture. The entire pupal stage occurs in soil. Therefore, for a part of their life cycle, fruit flies can be considered soil organisms. The pupal phase lasts from eight to ten days depending on temperature and humidity. The pupal phase is the one most vulnerable to abiotic stress and to many natural enemies, mainly predators and entomopathogens such as bacteria, fungi and nematodes which are also part of the soil biota (see Chapter 10). These antagonists play an important ES_HTSB_11-6 13/6/08 18:14 Page 175