Southwestern Entomologist (1998) 23, 137-145
N.C. Elliott, R.W. Kieckhefer, B.W. French and J.H. Lee (1998)
A comparison of size, sex ratio, and dispersal in three coccinellids
Southwestern Entomologist 23 (2), 137-145
Abstract: Relationships between body size, sex ratio, dispersal and abundance patterns of three congeneric coccinellids [Hippodamia convergens Guerin-Meneville, H. tredecimpunctata tibialis (Say), and H. parenthesis (Say)] were investigated. Sex ratio differed from 1:1 for H. tredecimpunctata and H. parenthesis; in both cases there was an excess of females. Sex ratio differed among years for all three species. Body size differed among sexes for two of the three species, with females being larger than males. Body size differed among years for all three species. A ranking of species with respect to relative variation in body size among years was H. parenthesis > H. tredecimpunctata tibialis > H. convergens. An identical arrangement of species was obtained when comparing the range of variation in sex ratio among years. A dispersal index, representing propensity for flight, displayed the opposite arrangement, being smallest for H. parenthesis and largest for H. convergens. If a population in a year was composed of large adults, larvae were abundant the next year for H. convergens and H. tredecimpunctata tibialis. If adults of these two species were abundant in a particular year there was a shift in sex ratio towards more males the following year. A high percentage of females in a particular year tended to result in an abundance of immatures the following year. Comparison of the size and sex ratio of coccinellids caught in agricultural fields and on flight interception traps stationed adjacent to fields indicated that males and females of each species from field collections were larger than those from traps. Sex ratios of beetles from fields did not differ from those from traps. Results are discussed in terms of the life history strategies of the three species that permit them to exploit spatially and temporally varying agricultural landscapes.
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Database assignments for author(s): B. Wade French, Jang-Hoon Lee
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
transmission/dispersal
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Hippodamia convergens (predator) | ||||
| Hippodamia tredecimpunctata (predator) | ||||
| Hippodamia parenthesis (predator) |
