常发性害虫白背飞虱与潜在性害虫电光叶蝉的种内竞争效应比较(英文)

实验室研究表明若虫期拥挤显著延长了白背飞虱Sogatellafurcifera的发育历期 ,但电光叶蝉Reciliadorsalis的历期受影响不显著 ;白背飞虱的若虫存活率、两种的性比、产卵前期和繁殖力不显著。若虫期高密度下的白背飞虱短翅率、电光叶蝉的若虫存活率显著降低。繁殖力和成虫寿命在成虫期也拥挤的条件下将进一步受到影响。特定年龄生命表分析表明拥挤对白背飞虱的综合影响程度比对电光叶蝉小。常发性、潜在性昆虫对若虫期、成虫期拥挤的反应并不总是如文献中所言表现为繁殖力的差异 ,本研究表明内禀增长力可较完整地描绘这种反应。白背飞虱作为一常发性昆虫与潜在性昆虫电光叶蝉的生态学特性的差异表现在 :未成熟期短、繁殖力和产出卵速率均高 ,因而内禀增长力也高。     

Effects of crowding on life history parameters of four green leafhoppers,Nephotettix spp. (Homoptera: Cicadellidae)

The effects of intraspecific crowding on the different life history parameters of the three tropical and subtropical green leafhoppers, Nephotettix virescensStål ,N. nigropictusDistant and N. malayanusIshihara etKawase , and one temperate species, N. cincticepsUhler , were studied under 25±1°C using the susceptible Japonica rice variety “Nipponbare”. Crowding during the immature stages of the four species prolonged the nymphal developmental period and resulted to smaller adults with reduced fecundity and shorter life span. Similarly, crowding during the adult stage also shortened the life span of both sexes of adults and decreased the fecundity of females of the four species. The effect of crowding during the adult stage was more adverse than the effect of crowding during the immature stages. N. cincticeps seemed more sensitive to crowding even at lower densities whereas the three tropical species were sensitive mostly at higher densities.     

Life table and biological studies of Harmonia axyridis Pallas (Col., Coccinellidae) reared on the grain moth eggs of Sitotroga cerealella Olivier (Lep., Gelechiidae)

The developmental period of immature stages, survival per cent, longevity, fecundity and life table parameters of Harmonia axyridis by feeding on fresh and frozen grain moth eggs (GME) of Sitotroga cerealella were studied under laboratory conditions. The effect of crowding adults on fecundity of females was also determined. The total developmental time from egg hatching to adult eclosion ranged from 18.89 ± 0.32 to 22.5 ± 0.21 days on fresh and frozen GME, respectively. Survival per cent from egg hatching to adult emergence differed significantly when the predator fed on the two diets of GME. Also, pupal and adult weights were affected by feeding on fresh and frozen GME. There were no significant differences in longevity of females, while there were significant variations in fecundity of females and longevity of males. The calculated values of T , DT , R_o , r_m , and e^rm were high by feeding on fresh GME. Morever, rates of survivorship ( Lx ), and maximum oviposition per female per day ( Mx ) were higher when the predator was reared on fresh than on frozen GME. Crowding conditions of predator adults affected the fecundity of females due to egg cannibalism by both males and females of the predator.     

Suitability of four different prey species for Dichochrysa tacta (Neuroptera: Chrysopidae)

The prey suitability for generalist insect predators is an important factor in efficient mass rearing. This work constitutes the first biological study of the predatory lacewing Dichochrysa tacta. We tested the effects of four different prey species on the biological parameters of the predatory lacewing D. tacta under laboratory conditions. These prey species consisted of Ephestia kuehniella (Zeller) and the aphids: Aphis fabae, Aphis punicae and Macrosiphum rosae. The results showed that prey species elicited a significant effect on preimaginal development times, survival, adult longevity and fecundity. In contrast, the progeny sex ratio, egg hatch and egg duration were not significantly affected by prey species. Eggs of E. kuehniella were the most suitable prey among those tested, and led to high survival rates, short development times for the preimaginal stages, long adult longevity, high fecundity, highest intrinsic rate of increase (r_m) and highest net reproductive rate (R₀) of D. tacta. Nymphs of both A. punicae and M. rosae were also relatively favourable prey, whereas nymphs of A. fabae were less suitable and resulted in reduced development, survival, adult longevity, fecundity, r_m and R₀. These results could be useful for optimising the mass rearing of D. tacta as an indigenous predator and for understanding its population dynamics in relation to different prey species in the field.     

The effect of different host plants on the reproduction and longevity of Nysius natalensis

Nysius natalensis Evans (Hemiptera: Orsillidae) is a pest of sunflower in South Africa. Adults invade sunflower fields from their weedy hosts which occur inside crop fields and on surrounding headlands. The host plant suitability for survival and reproduction as well as the effect of within‐generation host switching was studied on different wild host plants and sunflower. Life history parameters used to assess host plant suitability were F₁ adult survival, pre‐oviposition period, fecundity, and longevity. Nymphs and adults were provided with stems and seeds of five host plants, viz., Amaranthus hybridus L. (Amaranthaceae), Portulaca oleracea L. (Portulacaceae), Chenopodium album L. (Chenopodiaceae), Conyza albida Spreng. (Asteraceae), and sunflower, Helianthus annuus L. (Asteraceae). Nymphs were reared on crushed seed of the five plant species. After completion of the nymphal stage, emerging adults of each host plant group were provided with seed of a different host plant species for food. Adults did not survive long on stems only and very few eggs were laid. Seeds of the host plant species were shown to be an essential source of nutrients for N. natalensis reproduction, whereas the vegetative plant parts were unsuitable. Nymphal food and host‐plant switching between the nymphal and adult stages significantly affected the pre‐oviposition period. Nymphal and adult food source also affected female longevity. The number of eggs laid was not influenced by nymphal food, but was influenced by adult food and the switch between nymphal and adult food. The comparative attractiveness of sunflower and wild host plants for oviposition was also investigated and showed that females preferred to lay eggs on wild host plants, compared with sunflower. These results may explain why N. natalensis will lay their eggs on sunflower after weeds in the vicinity are controlled, or senesce toward the end of the growing season.     

Population characteristics of Macrocheles glaber (Acari: Macrochelidae) and Stratiolaelaps scimitus (Acari: Laelapidae) reared on a mushroom fly Coboldia fuscipes (Diptera: Scatopsidae)

Subterranean predatory mites are important biological control agents of pests in soil. In order to understand the population characteristics of two predatory mites, Macrocheles glaber Miiller and Stratiolaelaps scimitus Womersley, we studied their development, survival and fecundity data under laboratory conditions using Coboldia fuscipes Meigen as a food source and analyzed them with the age-stage, two-sex life table. Macrocheles glaber had a significantly shorter developmental time, oviposition period, longevity and lower fecundity than those of S. scimitus. The intrinsic rate of increase (λ), finite rate of increase (r), net reproductive rate (C0),net predation rate (C0), and finite predation rate (ω) of M. glaber were significantly lower than those of S. scimitus. Both population parameters and computer simulation implied that S. scimitus is a potential powerful biocontrol agent compared to M. glaber.     

Female mate choice of male signals is unlikely to promote ecological adaptation in Enchenopa treehoppers (Hemiptera: Membracidae)

A key question in speciation research is how ecological and sexual divergence arise and interact. We tested the hypothesis that mate choice causes local adaptation and ecological divergence using the rationale that the performance~signal trait relationship should parallel the attractiveness~signal trait relationship. We used female fecundity as a measure of ecological performance. We used a species in the Enchenopa binotata treehopper complex, wherein speciation involves adaptation to novel environments and divergence in sexual communication. We used a full‐sibling, split‐family rearing design to estimate genetic correlations (r_G) between fecundity and signal traits, and compared those relationships against population‐level mate preferences for the signal traits. Animal model estimates for r_G between female fecundity and male signal traits overlapped zero—rejecting the hypothesis—but could reflect sample size limitations. The magnitude of r_G correlated with the strength of the mate preferences for the corresponding signal traits, especially for signal frequency, which has the strongest mate preference and the most divergence in the complex. However, signal frequencies favored by the population‐level mate preference are not associated with high fecundity. Therefore, mate preferences do not appear to have been selected to favor high‐performance genotypes. Our findings suggest that ecological and sexual divergence may arise separately, but reinforce each other, during speciation.     

How do food quality and larval crowding affect performance of the autumnal moth,Epirrita autumnata?

Outbreak densities of autumnal moth, Epirrita autumnata (Borkhausen) (Lepidoptera: Geometridae), lead to high larval crowding. Phenotypic responses of E. autumnata to larval crowding and to food quality were studied by measuring growth and consumption as well as pupal weight and fecundity. Crowding may trigger increased consumption and faster development to avoid impending food shortage on good quality food. This is suggested by the result that on a good‐quality diet, the growth of crowded larvae was better than that of solitary larvae, though they did not consume more food than solitary larvae. Crowded larvae also completed the last instar earlier than solitary larvae. The fecundity of crowded autumnal moths was not lower than the fecundity of solitarily grown autumnal moths. This may provide conditions for extra rapid population build‐up of E. autumnata. During the population increase phase the crowding effect may facilitate larval performance; however, at peak density the crowding starts to have negative effects on the performance of larvae. On a poor‐quality diet, the performance of crowded and solitary larvae did not differ. The growth of larvae was better on a good‐quality diet than on a poor‐quality diet, due to higher efficiency in food utilization. Larvae feeding on low‐quality diet did not prolong their development time, but pupated at smaller size; this resulted in lower fecundity. A decrease in food quality can be seen as a cue of oncoming food shortage and resource depletion; it may be advantageous to pupate at a smaller size and ensure survival till reproduction, rather than risk prolonging development to achieve larger size and higher fecundity.     

Age‐ and temperature‐dependent oviposition model of Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) with Tetranychus urticae as prey

In this study, we developed an oviposition model of Neoseiulus californicus (McGregor) with Tetranychus urticae Koch as prey. To obtain data for the model, we investigated the longevity, fecundity and survivorship of adult female N. californicus at six constant temperatures (16, 20, 24, 28, 32 and 36°C), 60–70% RH and a photoperiod of 16 : 8 (L : D) h. Longevity (average ± SE) decreased as temperature increased and was longest at 16°C (46.7 ± 5.25 days) and shortest at 36°C (12.8 ± 0.75 days). Adult developmental rate (1/average longevity) was described by the Lactin 1 model (r² = 0.95). The oviposition period (average±SE) was also longest at 16°C (29.8 ± 2.93 days) and shortest at 36°C (6.7 ± 0.54 days). Fecundity (average±SE) was greatest at 24°C (43.8 ± 3.23 eggs) and lowest at 36°C (15.9 ± 1.50 eggs). The oviposition model comprised temperature‐dependent fecundity, age‐specific cumulative oviposition rate and age‐specific survival rate functions. The temperature‐dependent fecundity was best described by an exponential equation (r² = 0.81). The age‐specific cumulative oviposition rate was best described by the three‐parameter Weibull function (r² = 0.96). The age‐specific survival rate was best described by a reverse sigmoid function (r² = 0.85).     

Body condition (Wr) and reproductive potential of bighead and silver carp hybrids: Postzygotic selection in the Mississippi River Basin

Invasive bighead (Hypophthalmichthys nobilis) and silver carp (H. molitrix) are reproductively isolated in their native range, but form a bimodal, multigenerational hybrid swarm within the Mississippi River Basin (MRB). Despite observed F₁ hybrid superiority in experimental settings, effects of postzygotic selection on bighead and silver carp hybrids have not been tested in a natural system. Individual parent and hybrid genotypes were resolved at 57 species‐specific loci and used to evaluate postzygotic selection for body condition (W_r) and female reproductive potential (presence of spawning stage gonads and gonadosomatic index [GSI]) in the MRB during 2009–2011. Body condition in the Marseilles Reach, Illinois River declined with a decrease in species‐specific allele frequency from 1.0 to 0.4 for each species and early generation hybrids (F₁, F₂, and first‐generation backcross) had lower mean W_r than late generation hybrids (2nd+ generation backcrosses) and parentals. Proportions of stage IV and stage V (spawning stage) female gonads differed between bighead and silver carp, but not among parentals and their early and late generation hybrids within the MRB. Mean GSI values did not differ between parentals and hybrids. Because reproductive potential did not differ between hybrids and parentals, our results suggest that early generation hybrids occur in low frequency either as a factor of poor condition (W_r) and postreproductive survival, infrequent reproductive encounters by parental bighead and silver carp, or selection pressures acting on juvenile or immature life stages. Our results suggest that a combination of genetic and environmental factors may contribute to the postzygotic success of bighead and silver carp hybrids in the Mississippi River Basin.     

Effects of the susceptibility of rice varieties to Sogatella furcifera on nymphal development and reproduction of Microvelia horvathi through a food chain

The effects of four rice varieties highly susceptible （ Xiang-Zao-Xian31 and Jia-Yu 164 ）, moderately susceptible （ Wei-You402 ）, and resistant （ Zhu-Liang-You02 ） to the whitebacked planthopper Sogatellafurcifera on the nymphal development, reproduc- tion and survival of Microvelia horoathi were investigated through a food chain using SogateUafurcifera as herbivore prey. Significant longer nymphal developmental time were observed in the 1 st, 4th, 5th instar and whole nymphal stage of M. horvathi raised on S. furcifera fed ZLY02 and WY402 than those of the other two varieties. M. horvathi raised on S. furcifera fed resistant ZLY02 showed a significant lower survival of whole nymphal stage than those fed other three susceptible varieties. Moreover, M. horvathi raised on S. furcifera fed resistant ZLY02 had shorter female longevity and lower lifetime fecundity than those of on susceptible XZX3l. Our results suggest that the S. furcifera- resistant rice variety ZLY02 had a negative effect on the growth and development of the predator M. horvathi through a food chain.     

Impact of inter‐ and intra‐specific competition among larvae on larval,adult, and life‐table traits of Aedes aegypti and Aedes albopictus females

1. Few studies have taken a comprehensive approach of measuring the impact of inter‐ and intra‐specific larval competition on adult mosquito traits. In this study, the impact of competition among Aedes aegypti (L.) and A. albopictus (Skuse) was quantified over the entire life of a cohort. 2. Competitive treatments affected hatch‐to‐adult survivorship and the development time to adulthood of females for both species but affected the median wing length of females only for A. albopictus. Competitive treatments had no significant effect on the median adult female longevity nor were there any effects on other individual traits related to blood feeding and reproductive success. 3. Analysis of life table traits revealed no effect of competitive treatment on the net reproductive rate (R₀) but there were significant effects on the cohort generation time (T_c) and the cohort rate of increase (r) for both species. 4. Inter‐ and intra‐specific competition among Aedes larvae may produce individual and population‐level effects that are manifest in adults; however, benign conditions may enable resulting adults to compensate for some impacts of competition, particularly those affecting blood‐feeding success, fecundity, and the net reproductive rate, R₀. The effect of competition, therefore, affects primarily larva‐to‐adult survivorship and the larval development time, which in turn impacts the cohort generation time, T_c, and ultimately the cohort rate of increase, r. 5. The lack of effects of the larval rearing environment on adult longevity suggests that effects on vectorial capacity owing to longevity may be limited if adults have easy access to sugar and bloodmeals.     

Morphological and biological notes on Encarsia meritoria Gahan (Hymenoptera,Aphelinidae), a parasitoid of Trialeurodes vaporariorum (Westwood) (Homoptera,Aleyrodidae) new in Europe

Encarsia meritoria Gahan, a Neartic species recorded only in the USA, was found naturally occurring in Catalonia (north‐east Spain) in 1987. The morphology of immature stages, the rate of development in the range 12°C‐34°C, the longevity and fecundity at 24°C and some observations on its searching and host feeding behaviour are presented in this paper. Mean development times from egg laying to adult emergence ranged from 75 days at 12° C to 11 days at 28°C. The Lower Developmental Threshold computed from linear regression equations was 9°C. Females laid an average of 198 eggs (range 89–330) in an average of 34 days (longevity range 19–54 days). The intrinsic rate of increase at 24° C was 0.1717, slightly greater than the r_m of T. vaporariorum and smaller than the values reported for E. tricolor and E. formosa, which is not very promising for biological control. However, this may not be a definitive conclusion, because factors other than those considered in our experiments may play an important role infield conditions.     

Book Review

Two factors were examined to determine their effect on the life history, reproduction and life table parameters in the predacious mite Paraseiulus talbii (Athias-Henriot), cultured in the laboratory at 32°C and 75% RH, using tydeid mite, Orthotydeus californicus (Banks) as food. The factors investigated included age of mating females and food deprivation periods during adult stage. Age of mating females has an influence on fecundity and adult longevity; old females decreased egg production and shortened adult longevity compared with young females under constant conditions of abundant prey. A significant lower fecundity, shorter oviposition period and adult longevity were recorded on females when exposed to different food deprivation programmes. Old mating females (30-days old) as well as females exposed to severe food deprivation (three days starvation/a week) resulted in the lower net reproductive rate (Ro), intrinsic rate of natural increase (r_m) and finite rate of increase (λ) values (Ro = 7.301 and 7.486, r_m = 0.202 and 0.198, λ = 1.224 and 1.219) compared with young females (0-day old) and without food deprivation (Ro = 41.312, r_m = 0.308, λ = 1.361). The influence of the duration of copulation on egg production was also studied. Artificial curtailment of copulation to half or quarter the average duration resulted in a reduction in the percentage of reproducing females, fecundity, oviposition duration and the proportion of females in the progeny.     

Effect of some food sources associated with cassava in Africa on the development, fecundity and longevity of Euseius fustis (Pritchard and Baker) (Acari: Phytoseiidae)

Various foods associated with cassava were tested for their effect on the development, fecundity and longevity of Euseius fustis, the most common phytoseiid species found on cassava in Africa. Euseius fustis developed successfully to adulthood on the spider mite prey species Mononychellus tanajoa (Bondar) and Oligonychus gossypii (Zacher) and on pollen from maize, castor bean and cassava. Euseius fustis also completed development on water-diluted phloem exudate from cassava, diluted honeydew from the cassava mealybug and on various pollen and prey combinations. When reared on Tetranychus urticae Koch prey or free water only, E. fustis did not develop past the deutonymphal stage. All larvae held on clean leaf discs on water-soaked cotton died without moulting, suggesting that E. fustis must feed in order to moult to the nymphal stages. Diets of maize plus castor bean pollen and maize pollen plus M. tanajoa resulted in the highest rate of development, the highest fecundity and the greatest longevity. Castor bean pollen alone and maize pollen alone produced a higher fecundity and greater longevity than M. tanajoa tested alone. A colony of E. fustis reared continuously for seven generations on castor bean pollen produced nine times more adult females than a colony of E. fustis reared continuously on M. tanajoa. No negative effects on the development and fecundity of E. fustis were observed after seven generations were reared on pollen.     

灰飞虱与褐飞虱种内和种间密度效应比较

在人工气候室内比较研究了灰飞虱和褐飞虱在汕优63和秀水11上的种内和种间密度效应对其主要生物学参数的影响,结果表明两种稻飞虱均存在显著的种内竞争,主要表现为随着密度增加,若虫发育历期延长、若虫羽化率下降、雌成虫寿命缩短、每雌产卵量下降。种内密度效应与稻飞虱种类和寄主品种有显著互作关系,灰飞虱种内竞争较褐飞虱明显,二者在适宜寄主上种内竞争更为明显。同时,两种稻飞虱存在着显著的种间密度效应,主要表现为异种存在时的促进作用,即异种共存时若虫历期缩短、若虫羽化率提高、雌虫寿命延长、每雌产卵量增加。种间密度效应也与稻飞虱种类和寄主品种有显著互作关系,两种共存对灰飞虱的有利作用显著大于对褐飞虱的有利作用,在欠适宜寄主上种间互利效应更为明显。最后,本文对稻飞虱种内和种间密度效应的机制和进化意义进行了讨论。     

Development,survival and reproduction of Orius niger (Hemiptera:Anthocoridae) under different photoperiod and temperature regimes

The successful use of the predatory bug Orius spp. (Hemiptera:Anthocoridae) for the biological control of pests, namely western flower thrips Frankliniella occidentalis (Pergande), in greenhouses during winter depends on overcoming the obstacles of short photoperiods and low temperatures which limit the efficacy of the predators through diapause induction, slowed development, reduced survival and reproduction. Thus, research has focused on determining the insect species least vulnerable to these problems. This study investigated the effect of varying day-lengths (9, 11, 13 and 16 h) at 26°C as well as constant (18, 22, 26 and 30°C) and fluctuating (10/22°C) temperatures on biological characteristics of Orius niger (Wolff). Photoperiod did not induce reproductive diapause and did not significantly affect development, survival of eggs and nymphs, longevity, fecundity or sex ratio; with the exception of the 16 h day-length which led to a shorter duration of nymphal development. Fluctuating temperatures and a constant temperature of 18°C increased the incubation period, duration of nymphal development, total developmental time, generation time and longevity, compared to the constant temperatures of 22, 26 and 30°C, but decreased fecundity compared to 22 and 26°C. On the other hand, sex ratio was not influenced by 10/22 and 18°C. Egg hatch rate and nymph survival differed significantly between temperature regimes, being lower at 18 and 10/22°C. These results suggest that O. niger would be able to survive and reproduce under winter conditions in unheated Mediterranean greenhouses and is a candidate for use in the biological control of pests.     

Differential response to larval crowding of a long‐ and a short‐lived medfly biotype

Response of endophytic fruit fly species (Tephritidae) to larval crowding is a form of scramble competition that may affect important life history traits of adults, such as survival and reproduction. Recent empirical evidence demonstrates large differences in adult life history traits, especially longevity, among Mediterranean fruit fly (Ceratitis capitata; "medfly") biotypes obtained from different regions of the world. However, whether the evolution of long lifespan is associated with response to stress induced by larval crowding has not been fully elucidated. We investigated, under constant laboratory conditions, the response of a short‐ and a long‐lived medfly biotypes to stress induced by larval crowding. Survival and development of larvae and pupae and the size of resulting pupae were recorded. The lifespan and age‐specific egg production patterns of the obtained adults were recorded. Our findings reveal that increased larval density reduced immature survival (larvae and pupae) in the short‐lived biotype but had rather neutral effects on the longed‐lived one. Only larvae of the long‐lived biotype were capable of prolonging their developmental duration under the highest crowding regime to successfully pupate and emerge as adults. Response of emerging adults to larvae crowding conditions was similar in the two medfly biotypes. Those individuals emerging from high larval density regimes had reduced longevity and fecundity. Long‐lived biotype individuals, however, appeared to suffer a higher cost in longevity compared with the short‐lived one. The importance of our findings to understand the evolution of long lifespan is discussed.     

Effects of four constant temperatures on the development of two Bradysia (Diptera: Sciaridae) species

In this study, the effects of temperature on the growth, development, survival, fecundity and other population parameters of two local Bradysia species B. odoriphaga and B. impatiens were studied at four constant temperatures (25, 28, 31 and 34°C). The results show that 25°C is the optimum temperature for the growth and development of B. odoriphaga, while 28°C is more favourable for B. impatiens. The temperature of 31°C restricted the growth and development, while the temperature of 34°C inhibited the eggs hatching in both species, resulting in no egg survival and no subsequent development. High temperatures (>28°C) prolonged the 4th larval stage duration, mean generation time (T) and population doubling time (Dt) of both species. The high temperature of 31°C greatly shortened the female longevity, weakened the oviposition and reduced the survival of both species. Moreover, the life table parameters R₀, r_m and λ were also suppressed by this high temperature. However, the high temperature of 31°C had little impact on the egg survival, pupal weight and male longevity. In addition, at 31°C, the values of R₀, r_m and λ of B. odoriphaga were higher than those of B. impatiens, suggesting that B. odoriphaga is more tolerant to high temperature than B. impatiens. The differences between two Bradydsia species seem determined genetically. Our findings are important for better understanding their biological characteristics at a certain constant temperature and demonstrate the possibility to control and manage those two Bradysia species by increasing ambient temperature.     

The effect of crowding on alate production and weight of apterous exules of the apple-grass aphid, Rhopalosiphum insertum

Offspring of Rhopalosiphum insertum are most sensitive to crowding immediately before and after birth. Crowding throughout the nymphal and adult life of the mothers irreversibly determines most offspring as alatae whether the offspring are crowded or not. Offspring of mothers having less exposure to crowding require additional stimuli after birth. The possible evolutionary advantages of such a system are discussed. Hormonal control of alary polymorphism is implicated. The weight of apterae declined with increased crowding. This is correlated with an increase in alate production, and may thus serve to limit the population increase to a level tolerable by the plant without killing it.