Effect of temperature and host plant on the development of the blackfaced leafhopper

Abstract

Population dynamics of the blackfaced leafhopper, Graminella nigrifrons (Forbes) (Homoptera: Cicadellidae), was studied at five temperatures (18, 21, 24, 27, & 30 °C) in the laboratory on seedling maize (Zea mays L.), oats (Avena sativa L.), and the perennial johnsongrass (Sorghum halepense (L.) Pers.). Effects of temperature and host plant on egg to adult mean development time, adult size and weight, and fecundity were determined. Leafhoppers on all three hosts developed fastest at the highest temperature tested (21.3 days), and slowest at the lowest temperature tested (73.2 days). The duration from first to last adult eclosion was shortest at 30 °C, (11.5 days) and longest at 18 °C (43 days). The sex ratio of males to females did not differ from 1:1, but males developed an average of 1.2 days faster than females on all three hosts. Mean percent development/day ranged from 1.4% at 18 °C to 4.7% at 30 °C. The relationship of this development rate and temperature was determined using both a linear model and a variable parameter biophysical model. Based on these models, the developmental threshold is estimated at 12–15 °C. The lowest temperature yielded larger and heavier adults (312 μg, dry weight) than did the highest temperature (225 μg). Fewer leafhoppers developed on the perennial than the annuals at 30 °C and fewer on the annuals than the perennial at 18 ° C. Our results suggest that early in the season johnsongrass and perhaps other perennials are the superior developmental hosts for this leafhopper, whereas in midsummer when temperatures are highest, annuals are the better hosts. Résumé Effet de la température et de la plante‐hôte sur le développement de Graminella nigrifrons La dynamique des populations (durée de développement de l'œuf à l'adulte, poids et taille des adultes, fécondité) de G. nigrifrons Forbes (Homop. Cicadellidae) a été étudiée au laboratoire à 5 températures sur plantules de maïs (Zea mays L.), avoine (Avena sativa L.) et sorgho vivace (Shorgum halepense (L.) Pers.). Sur les 3 plantes, les mâles se développent en moyenne 1,2 j plus vite que les femelles. Les relations entre vitesse de développement et température ont été déterminées en utilisant à la fois un modèle linéaire et le modèle biophysique à 2 paramètres de Sharpe & DeMichele (1977). Les températures plus basses donnent des adultes des 2 sexes plus gros et plus lourds. Moins de G. nigrifrons se sont développés sur la graminée vivace que sur les 2 graminées annuelles à la température la plus élevée (30 °C), tandis qu'à la température la plus basse (18 °C) moins de cicadelles se sont développées sur les graminées annuelles. La température semble jouer un rôle significatif en déterminant l'adéquation des plantes comme hôtes convenant au développement de G. nigrifrons. Le potentiel de ponte de cette cicadelle avait été sous‐estimé par les étudies précédentes.

Influence of Latitude and Elevation on Polymorphism Among Populations of the Corn Leafhopper,Dalbulus maidis(DeLong and Wolcott) (Hemiptera: Cicadellidae), in Brazil

“…Under laboratory conditions, Larsen and Nault (1994) observed increases in size, weight, and pigmentation of adults of Þve Dalbulus species when immatures were reared on mature maize at low temperatures and short day length, typical of late season conditions in Mexico. A similar relationship between rearing temperature and adult morphology has been reported for leafhoppers Empoasca fabae (Harris) (Simonet and Pienkowiski 1980) and Graminella nigrifrons (Forbes) (Larsen et al 1990). Polymorphism has also been observed along latitudinal and elevational gradients for several insect groups (Cushman et al 1993, Hawkins and Lawton 1995, Krasnov et al 1996, Smith et al 2000.…”

“…Regarding body pigmentation, differences in rearing condition affected pigmentation of D. maidis, D. elimatus, and D. gelbus, but not of D. quiquenotatus and B. tripsaci (Larsen and Nault 1994). For the black-faced leafhopper, G. nigrifrons, reared under Þve different temperatures, females were always bigger and heavier than males (Larsen et al 1990). The differences in weight and size between sexes of D. maidis may be related to the development rate: females develop more slowly than males; thus, they have more time to feed and grow (Larsen and Nault 1994).…”

“…Through a digital micrometer (Wild MMS 235 display and Wild Typ. 325400 ocular, Wild Heerbrugg Ltd., Heerbrugg, Switzerland) coupled to a stereoscopic microscope, each specimen was measured for the distance between the compound eyes in the head vertex, the length of the second medium cell of the fore wings (Larsen et al 1990), and the length of the ovipositor, from the hollow portion of the seventh sternite to its tip. The intensity of abdomenal pigmentation was evaluated as an indicator of body coloration.…”

Contrasting effects of sewage sludge and commercial fertilizer on egg to adult development of two herbivorous insect species

“…However, the slight differences in developmental time of the blackfaced leafhopper among treatments (Table 2) might have been separated if a cooler temperature had been used, such as 20 ° C, which would have lengthened the emergence period (Larsen et al, 1990).…”

“…The laboratory colonies of leafhoppers used in this study were originally started with adults collected from grasses at the Ohio Agricultural Research and Development Center, Wooster, Ohio (Larsen et al, 1990). Leafhoppers were reared on sweet corn seedlings at about the 4 to 5 leaf stage (Zea mays L.; cv.…”