摘要:

The rates of establishment of exotic natural enemies introduced against exotic pests in the orders Homoptera, Lepidoptera, and Coleoptera were found to be inversely related to (1) the number of species released at a given time and place and (2) the number of exotic incumbent species of natural enemies present. Thus, competitive exclusion of introduced natural enemies has probably occurred and contnbuted to the relatively low rate of establishment in biological control. It is suggested that, in cases in which less-than-complete control was obtamed through multiple-species releases, natural enemies capable of effective control of the target pest may have been competitively excluded. Because of this possibility, use of the empirical approach of releasing all available species of natural enemies, with the hope that the best species or combination of species will be sorted out in the field, should be questioned. In modern biological control, a more rational release strategy is in order.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.1

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

By reputation, ground beetles are known to be predators. However, neither carabid adults nor larvae come in contact with corn rootworms. Also, the rootworms have become adept in all stages at avoiding ground-dwelling predators. Carabids and rootworms have different habits, and they seldom come together. It is more accurate to call these carabids “opportunists” than predators.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.5

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

The phenology of fourChaoborusspecies in four bog lakes in the upper peninsula of Michigan was documented. The sequence timing of pupation was:Chaoborus americanus, early May;C. flavicans, end of May;C. punctipennis, early July;C. trivittatus, end of August and early September.C. americanus,C. punctipennis, andC. trivittatuseach occurred in two of the lakes. Differences in the timing of pupation for each of these species between lakes were not always correlated with environmental differences between lakes.C. punctipennis,C. flavicans, and one of theC. americanuspopulations was univoltine. The otherC. americanuspopulation may have been bivoltine. OneC. trivittatuspopulation appeared to be univoltine, whereas the other may have had a 2-year generation time. The significance of the sequence and timing of pupation of these species is discussed in relation to seasonality, interspecific competition, and predation.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.9

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

When females reared in the laboratory on artificial diet were gamma sterilized (LS) they became more receptive to the second mating than did normal ones (L), However sterilization reduced male effectiveness in second mating. Wild (W) females were found to mate more often when caged with LS males than when caged with W males. In mixed populations of W and LS flies, the latter tended to mate with each other at the first mating, but successive matings were more numerous between W females and LS males. After the first mating, ca. 0.21 matings per ♀-day were recorded between W females and LS males, as compared with 0.01 to 0.05 in each of the other three possible mating combinations during a 10-day period. It appears that, under laboratory conditions, W females were more receptive than LS females and LS males were more effective than W males to repeated mating.During first mating, W flies were always found to mate primarily in the last 2 h before scotophase, whereas L or LS flies mated in similar numbers during the 4 h before scotophase. After the first mating, mating activity in all fly types concentrated in the last 2 h before scotophase.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.17

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

The white cutworm,Euxoa scandens(Riley), was studied in commercial asparagus fields between 1973 and 1975. Monitoring adult flight activity with a blacklight trap revealed that male moths were more attracted to the blacklight than females. Males were found to have a unimodal flight activity pattern, whereas females exhibited a bimodal flight activity pattern. In Michigan the white cutworm was found to be univoltine with seven larval instars. Larval food selection was found to be random with equal probability that the larval food would feed on unharvested spears or the “butt” remnants of a harvested spear. Feeding behavior was one of the pnncipal components of plant damage.Four different larval sampling schemes were evaluated: baited and unbaited pitfall traps, baited barrier plots, and baited open plots. Pitfall traps baited with an apple pomace bait formulation of carbaryl caught significantly greater numbers of white cutworm larvae per day than unbaited traps. Baited barrier plots were found to be best for obtaining population density estimates; however, open baited plots were best for larval detection. The number of cutworm larvae trapped was highly dependent on trap orientation to the asparagus rows.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.21

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

A field study on the effects of repeated mowing on turf-inhabiting populations ofEndria inimicaSayOscinella fritL. was conducted. The insects were provided with a temporal choice of recently mowed turf versus turf not recently mowed.Endriasnowed no indication of lawn switching as a function of mowing, nor evidence of mowing-induced mortality.Oscinelladisplayed a strong mowing-related response. The frit files apparently move off of not recently mowed turf onto newly mowed turf, peak movement being detected at 1 h after mowing, but within 24 h no differences between the numbers of flies on recently mowed turf versus not recently mowed turf could be detected.The study suggests that, for the two turf-adapted species studied, mowing is not a negative factor, and that, forOscinella frit, it may even be beneficial.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.29

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Factors affecting the mortality ofColeomegilla maculata lengiTimberlake were investigated at Guelph, Ontario from 1976 through 1978. It was found that most of the overwintering mortality of caged beetles occurred at the end of the winter. Parasitism byPerilitus coccinellaeShrank reduced survivorship of overwintering beetles. There was no significant difference found in overwintering mortality of beetles caged at three different densities. Predation of eggs ofC. m. lengiwas 44.8 and 48.6% in 1976 and 1977, respectively. Stage-specific mortality for the coccinellids of the first generation in corn (primarilyC. m. lengi) at Guelph calculated for the period from egg to pupa was 93.8% in 1977. In 1978, mortality from egg to pupa ofC. m. lengiwas 95.4%.C. m. lengidisplays a type IV survivorship curve of Slobodkin.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.32

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Offspring of the dung beetle,Onthophagus gazella(F.), declined significantly in size and number as a result of increased parental density during nest construction. The parent beetles' ability to utilize the manure fully also declined with increased density. Offspring reared from brood balls provisioned with manure during the late stages of a nesting period were significantly smaller than offspring reared in balls provisioned during the early stages. Brood balls provisioned with manure of lower protein content yielded significantly smaller adults compared with adults from the stock manure. The role of these factors in beetle size determination and in the ecology of manure pats is discussed.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.38

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

Lymantria disparL. larvae infected with the gypsy moth nuclear polyhedrosis Virus were exposed toApanteles melanoscelus(Ratzeburg) females, separately and in combination. with noninfected larvae. Significant differences established among the number of parasite-host contacts and percent ovipositional attempts observed under various treatments indicated that the parasites preferred noninfected larvae, making fewer efforts to parasitize virus-infected individuals. Since the noninfected and virus-infected larvae were different in a number of ways, several factors may have contributed to the behavioral discrimination evidenced.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.42

出版商:Oxford University Press    

年代:1982

数据来源: OUP

摘要:

The effects of temperature and prey density on Coleomegilla maculata (DeGeer) feeding onMyzus persicae(Sulzer) were determined to quantify their impact on theC. maculata-M. persicaeinteraction. Seven temperatures ranging from 15.6 to 32.2° C were employed in the study. Nine prey densities per temperature and two predator and prey age classes per prey density were also used.An enzyme kinetic equation was used to describe the change with temperature in the green peach aphid intrinsic rates of increase and theC. maculatalarval and adult search rates. The larval and adult handling rates were determined to be linearly related to temperature over the range studied. The short-term impact ofC. maculataadults and 3rd-instar larvae on green peach aphids was simulated by substituting these equations into two aphid growth rate models. Both models predicted thatC. maculata3rd-instar larvae and adults would be most effective in reducing the aphid population in temperatures above 29° C.

ISSN:1754-5692    

DOI:10.1093/ee/11.1.46

出版商:Oxford University Press    

年代:1982

数据来源: OUP