Food consumption by larvae of three strains of Callosobruchus maculatus (Coleoptera: Bruchidae)

Comparison of life history and genetic properties of cowpea bruchid strains and their response to hypoxia

“…Following this idea, because mated females in our experimental setting were confined with males throughout their lives, the female adults were constantly harassed by their male partners, while receiving reduced ejaculate-derived nutrients, resulting in shorter longevity compared to unmated insects. Furthermore, adult lifespan was longer for females than for males, possibly due to more food consumption by the female larvae (Credland and Dick, 1987). Interestingly, insect strain had a significant effect on longevity of unmated but not mated adults, suggesting different resource acquisition during larval stages.…”

Host suitability, respiration rate and the outcome of larval competition in strains of the cowpea weevil, Callosobruchus maculatus

“…There is wide variation in biological traits among geographically distinct strains of C. maculatus (Dick & Credland 1984; Credland, 1986; Dick & Credland 1986; Credland & Dick, 1987; Messina, 1989; Messina et al ., 1991; Berg & Mitchell, 1993; Chiu & Messina, 1994; Savalli et al ., 2000). Expression of this variation is likely to be influenced by the host seed and may help toward understanding the local evolution of these strains and how they relate to their distinctive larval competition strategies, which range from the scramble to the contest type (Nicholson, 1954; Dick & Credland, 1984; Smith & Lessells, 1985; Smith, 1990; Toquenaga, 1990, 1993; Colegrave, 1994; Horng, 1997; Lale & Vidal, 2001; Takano et al ., 2001).…”

“…The process is a consequence of intrinsically disruptive selection on larval competition strategies, whereas the outcome also depends on how much resource is required for development in relation to what is available within a patch of resource (seed) (Smith & Lessells, 1985). Because high seed consumption and larval respiration rate have been associated with the Yemen strain (Credland & Dick, 1987; Daniel & Smith, 1994), which was described as approaching a contest‐type of larval competition outcome (Credland et al ., 1986), it was hypothesized that seed consumption and respiration would affect adult emergence and, consequently, the competition outcome assessed here as the number of adults emerged per seed. This would occur because higher larval respiration rates would be associated with high seed consumption leading to increasing interactions and mortality of larvae within a single seed.…”

“…The reported differences in larval respiration rate and per capita consumption of legume seeds in strains from Brazil and Yemen of C. maculatus (Credland & Dick, 1987; Smith, 1990; Daniel & Smith, 1994) may be of particular relevance for the larval competition outcome in strains of C. maculatus, with important applied consequences. Therefore, the objectives of the present investigation were to assess the overall response of different strains of C. maculatus when subjected to seeds of two different host species and to investigate how this response relates to the outcome of larval competition.…”

Variability in oviposition in four strains of Callosobruchus rhodesianus (Pic) from different geographical areas of Zimbabwe

“…A comprehensive series of The cowpea weevil, Callosobruchus rhodesianus experiments by Dick and Credland (1984;1986 a, (Pic.) Credland and Dick (1987) showed that biotypes The pest occurs everywhere in sub-Saharan Africa, (syn. Credland and Dick (1987) showed that biotypes The pest occurs everywhere in sub-Saharan Africa, (syn.…”