DEPTH OF PUPATION OF CARIBBEAN FRUIT-FLY (DIPTERA, TEPHRITIDAE) IN SOILS IN THE LABORATORY

Estimates of pupation depth in soil for Caribbean fruit flies, Anastre pha suspensa (Loew), are important to future development of sampling a nd management techniques in fruit groves in southern Florida. Colony-r eared, late third instars were placed onto soil surfaces in containers and allowed to burrow and pupate. Experimental units consisted of one larva per container. Soil in containers had a volume of 740 ml, surfa ce area of 95 cm2, and depth of 9 cm. Pupae were excavated from soil a fter 72 h and their depths were recorded. Soil moisture (10 and 50% fi eld capacity), type (muck, marl, and loam) and compaction (low and hig h bulk density) were the independent variables tested for their effect s on pupation depth. Mean depths ranged between 0.7 cm (loam, 50% fiel d capacity) and 3.3 cm (muck, 10% field capacity, low bulk density). M eans differed significantly because of compaction and the interaction of moisture x compaction. Larvae pupated at a greater depth in soils o f low compaction than in soils of high compaction. The difference in d epth between low and high compaction was greater for soils of low mois ture than for soils of high moisture. The pupation rate was 100% for a ll treatments. Mean adult emergence rates ranged between 66.7 and 100% but did not differ significantly among treatments.