摘要:

Bioassays were performed to determine the behavioral responses ofCoptotermes formosanusShiraki soldiers to ants or ant extracts.C. formosanusresponded differently to semiochemicals of different ant species. A significantly greater proportion of termite soldiers responded aggressively toPheidole megacephala(F.) than to other ant species. Termite soldiers were significantly less likely to respond aggressively toMonomorium floricola(Jerdon),Tetramorium simillimum(F. Smith), andOchetellus glaber(Mayr) than to other ant species. Termites avoided contact withO. glaberin 85.3% of trials, but only avoided contact with other ant species in 18% or less of trials. Termite soldiers were significantly more likely to respond to freshly killed ants than to solvent-treated ants of the same species. Termites also responded similarly to freshly killed ants and dead termites treated with ant extracts, indicating that termite responses were mediated, at least in part, by chemical cues. The ability ofC. formosanusto distinguish among different ant species on the basis of semiochemicals could be an adaptive response that allows them to recognize particularly threatening enemies.

DOI:10.1093/ee/23.6.1524

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Capillary tube evaporators arrayed in grids in tomato, alfalfa, and cotton fields released into the air four previously identified pheromone components, either separately or in various blend combinations, of the beet armyworm,Spodoptera exigua(Hübner). Disruption of pheromone communication in this species was measured by the decrease in the numbers of male moths orienting to female moths that were used as bait in traps in the centers of the grids. The only pheromone component that appeared essential to provide disruption of communication was (Z,E-9,12-tetradecadienyl acetate. Research comparing grids equipped with evaporators of four different sizes, each size spaced at three separations in the field, indicated that the spacing between evaporators, up to 4.6 m apart, was not the most critical factor determining the amount of disruption obtained. Rather, the most important factor appeared to be evaporator size; the largest evaporators, releasing 25 μg of the pheromone component per day, provided the highest amount of disruption, even when spaced in the field at the maximum tested separation. TheS. exiguapheromone component, (Z,E)-9,12-tetradecadienyl acetate, did not disrupt communication between males and females of the tomato pinworm,Keiferia lycopersicella(Walsingham), and theK. lycopersicellapheromone, (E)-4-tridecenyl acetate, did not disrupt communication between the sexes ofS. exigua.

DOI:10.1093/ee/23.6.1529

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

The nitidulid species,Carpophilus mutilatusErichson,C. hemipterus(L.),C. freemaniDobson, andC. obsoletusErichson, responded to their aggregation pheromones during a 17-mo study in a California date garden. The pheromones were dramatically synergized by volatiles from fermenting whole-wheat bread dough; pheromones alone attracted only 1.0–29% as many beetles as the combinations with dough, and dough alone attracted only 0–2.9% as many as the combinations. Unbaited controls caught noCarpophilus. C. mutilatuswas the most abundant species, and individual trap catches were as high as 63,500 per week. Cross attraction was significant in some cases, especially forC. mutilatusresponding to the pheromones ofC. hemipterusandC. obsoletusbut was minimal compared with responses to the species’ own pheromones. The pheromone ofC. lugubrisMurray was also tested, but noC. lugubriswere detected in the date garden. Two additional nitidulid species were caught consistently:C. (Urophorus) humeralis(F.) andHaptoncus luteolus(Erichson).C. humeralisresponded significantly to all of the pheromones but especially to those forC. hemipterus,C. lugubris,andC. obsoletusin combination with dough.H. luteoluswas attracted only to the dough. Adult beetles were present in the dates on the ground throughout the year, but flight activity, as measured by trap catch, occurred erratically. All species had an intense period of flight activity in April and May, following a winter with favorable rains and an abundant food supply. This flight terminated abruptly when dates spilled to the ground during harvest and were hydrated bya rain storm. Flights ofC. freemani,C. obsoletus,C. humeralis, andH. luteoluswere more frequent in summer than forC. mutilatusorC. hemipterus.Flight activity during December and January was low for all species, but there was great variability in patterns of flight activity. The use of these pheromones is discussed in relation to pest management.

DOI:10.1093/ee/23.6.1534

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

The mating behavior of the desert locust,Schistocerca gregaria(Forskal), was studied in the laboratory to explore the hypothesis that long-range communication signals may be operative in the solitarius phase. Before mating, males actively scanned the visual field, frequently cleaned their antennae and compound eyes, and jumped toward the females. The females, in response, moved slowly in front of the males and vibrated their entire bodies. Males assaulted and grasped the females, which at first tried to kick off the males using their hind legs but eventually submitted. In wind tunnel experiments with hidden females, males spent ≍33% of their time in searching and>80% were able to locate females, whereas, in the absence of the hidden females stimulus, they spent little time (<5%) in searching and remained in a resting state near the release point. In the presence of hidden females, the males also scanned and jumped more frequently, whereas they did not actively scan or jump in the absence of hidden females. When males were held in wire screen cages and females released downwind, the females did not respond to the males, indicating that males search for females when mating. Blinded males showed no interest in feeding or mate finding. Suppression of acoustic signals by gluing female wings did not significantly affect the male response. These studies affirm, for the first time, the emission of a sex pheromone by the solitarius females that attracts males.

DOI:10.1093/ee/23.6.1544

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

A field cage evaluation of the parasitoidEretmocerusnr.californicusas a biological control agent ofBemisia argentifoliiBellows&Perring was conducted in Southern California cotton during June through August of 1992. Percentage of parasitism was highest in early August at 61% in the high parasitoid release treatment and was significantly higher than both the low parasitoid release and control treatments. The density ofB. argentifoliipupae on leaves in the high parasitoid release treatment was approximately one-fifth of the other treatments. Seed cotton yield was significantly higher in the high parasitoid release cage in comparison with those of the low parasitoid release and control cages. We conclude thatE.nr.californicusmay be a useful control agent in an augmentative release strategy against whitefly on cotton and is deserving of large-scale, open field studies.

DOI:10.1093/ee/23.6.1552

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Effects of plant-host type, either wheat,Triticum aestivumL., or oat,Avena sativaL., and the fungal entomopathogenBeauveria bassiana(Balsamo) Vuillemin, on numerical and spatial distributions of Russian wheat aphid,Diuraphis noxiaKurdyumov, populations were investigated. Untreated adult aphids or aphids inoculated with conidial suspensions of the pathogen were released onto the center seedlings of an Bl-seedling grid in a cage. After 17 d, the numbers of live adults, live nymphs, and sporulating cadavers were recorded for each plant, along with plant height and dry weight. Aphid populations were consistently lower on oat than on wheat, and lower inB. bassianatreatments. Spatial statistics (geostatistics) were used to compare patterns of aphid distribution on plants. On wheat without the pathogen present, adult aphid populations were highest in approximately concentric rings near the outermost plants in grids. Addition ofB. bassianato the system reduced the amount of variation caused by spatial orientation, thereby changing the spatial distribution of aphid populations. On oat, aphid populations generally were highest near the center of the grid, but addition of the pathogen changed the spatial structure of the aphid population. Results suggest that aphid movement behavior, which is intimately linked to host-plant quality, is an important determinant of epizootic proliferation. Elucidation of these relationships may eventually lead to a synergistic use of microbial control agents and host-plant resistance in pest management strategies.

DOI:10.1093/ee/23.6.1558

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

A faunistic study was conducted over a four year period in apple orchards utilizing different pesticide management strategies to determine the parasitoid complex of the tufted apple bud moth,Platynota idaeusalis(Walker). The relative effectiveness of these parasitoids as control agents in conventional orchards using broad-spectrum insecticides was compared to those using pheromone-mediated mating disruption to controlP. idaeusalis.Limited samples were also taken of other tortricids found in these orchards to determine if they were serving as alternate hosts forP. idaeusalisparasitoids. Thirty-one parasitoid and two hyperparasitoid species were recovered during this study which, when combined with other records, present a total parasitoid complex of 41 species forP. idaeusalis.Total parasitism was higher for summer broodP. idaeusalislarvae in mating disruption orchards than in conventional orchards. Total parasitism of the overwintering brood ofP. idaeusaliswas higher than the summer brood in conventional orchards. Rates of parasitism were comparable in mating disruption blocks during both broods. The ichneumonExochus atricepsWalsh. was the most common parasitoid species, and it attacked both broods ofP. idaeusalis.The braconidsMeteorus trachynotusViereck,Bassus anulipes(Cresson),B. cinctus(Cresson),Apanteles polychrosidisViereck, and anApantelessp. nearedwardsiiRiley were also common but they attacked only the overwintering brood. Four undescribed species of braconids were found during this study.

DOI:10.1093/ee/23.6.1568

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

MAINTENANCE OF BIODIVERSITY and environmental quality through conservation and restoration of natural ecosystems are themes which resonate deeply with many biologists. While the ecological arguments stressing the need for habitat restoration are compelling, access to information on principles and specific techniques is limited. I was, therefore, very intrigued by the promise of a volume entitled theLandscape Restoration Handbook.When the book arrived, the first thing that struck me was the cover photo picturing a golf course on a misty morning. This did not necessarily meet my preconceived notions of a landscape restoration project, but did prompt me to turn to the forward to find out more about the purpose and background of this volume.

DOI:10.1093/ee/23.6.1580

出版商:Oxford University Press    

年代:1994

数据来源: OUP