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The timing of oviposition and larval growth by two tephritid fly species in relation to host‐plant development
Author(s) -
STRAW N. A.
Publication year - 1989
Publication title -
ecological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.865
H-Index - 81
eISSN - 1365-2311
pISSN - 0307-6946
DOI - 10.1111/j.1365-2311.1989.tb00946.x
Subject(s) - biology , achene , larva , host (biology) , tephritidae , botany , ecology , zoology , pest analysis
Abstract. 1. The relationships between the timing of oviposition, larval establishment and host development were studied in the tephritids Tephritis bardanae (Schrank) and Cerajocera tussilaginis (Fab.) which attack flowerheads of Arctium minus (Hill) Bernh. (Compositae). 2. T. bardanae laid eggs in small sized flowerheads that were at an early stage of development, and appeared to use the external dimensions of the head as an oviposition cue. In contrast, C. tussilaginis females laid eggs into heads that were near to flowering and the timing of their attack was most closely related to particular lengths of florets and achenes inside the head. Both tephritids apparently recognized suitable heads by comparing aspects of their own body size with the size of particular flowerhead structures. 3. Individual heads were suitable for oviposition for a period of 10–11 days for both species, but the periods of susceptibility to each species did not overlap. 4. Attack by T. bardanae was timed to exploit the flowering phase of flowerhead development. Larval establishment and early development were synchronized with increasing nutrient availability occurring during the rapid growth of the florets and achenes before and during anthesis. 5. In contrast, the later attack by C. tussilaginis was timed to exploit the seed maturation phase of head development. Individual C. tussilaginis larvae operated as highly specialized ‘achene parasites’, utilizing the influx of nutrients into single achenes after fertilization. 6. Larvae of both tephritids induced abnormal host‐tissue growth, but oviposition in both species was timed primarily to synchronize larval development with natural periods of high nutrient availability inside flowerheads, rather than with the presence of tissues suitable for gall induction.