Oviposition Regularity of Hybrid Silkworm Stock Moth of Liangguang No. 2

To cure pebrine using dry - hot air treatment of silkworm eggs, and control egg age within 12 hours, oviposition regularity of hybrid silkworm stock moth of Liangguang No. 2--current production variety in Guangdong Province was investigated. The experiment showed that most hybrid stock female moths of Liangguang No. 2 at 25 -28℃ oviposited in the first 5 hours, and egg production declined sharply after 5 hours. 7 · Xiang × Fu · 9 achieved the oviposition peak within 1 hour after casting the moth, the oviposition amount within 5 horns accounted for 92.94% of the total oviposition amount of female moth, that within 9 hours accounted for 96.47%. Fu · 9 × 7 · Xiang achieved the oviposition peak within 2 -4 hours after casting the moth, the oviposition amount within 5 hours accounted for 85.21% of the total oviposition amount of female moth, that within 9 hours accounted for 92.78%. Oviposition regularity of the hybrid silkworm stock moth of Liangguang No. 2 meets the need of dry-hot air treatment of silkworm pebrine-control egg age within 12 hours.

Oviposition Site Selection of Anoplophora glabripennis in Sugar Maple (Acer saccharum) and Its Gnawing Nidus Oviposition Habits

[Objective] The paper was to explore the oviposition site selection of Anoplophora glabripennis in sugar maple and its gnawing nidus oviposition habits. [Method] Through field and indoor rearing observation, the oviposition site selection of A. glabripennis in sugar maple was studied, and the gnawing nidus oviposition habits were analyzed. [Result] The height of oviposition site of A. glabripennis in sugar maple, the number observation holes （gnawing nidus oviposition points） and bark thickness in oviposition site showed linear correlation with diameter of branch at breast height. The gnawing nidus oviposition habit of A. glabripennis in sugar maple was mainly divided into 4 stages： gnawing nidus site selection, gnawing nidus, oviposition and nidus sealing, the duration from gnawing nidus to nidus sealing was（38.29±16.47）min. [Conclusion] The study provided reference for comprehensive prevention of A. glabripennis in greening tree species sugar maple, as well as further study on reproductive behavior and regulation mechanism of A. glabripennis.

Impact Evaluation of Insect-Resistant Transgenic Rice on the Feeding and Oviposition Behavior of Its Non-Target Insect, the Brown Planthopper, Nilaparvata lugens (Homptera: Delphacidae)

The feeding and oviposition behavior of the brown planthopper (BPH), Nilaparvata lugens on two transgenic indica rice homogenous genotypes (B1 and B6) with cry1Ab gene from Bacillus thuringiensis and transgenic restored line of hybrid rice (MSA) with SCK gene (a modified CpTI gene) were measured, compared with those on their corresponding non transgenic parental cultivars Jiazao935 and Minghui86 performed by BPH. Under the selection condition of host plants by BPH, loading percentage, oviposition preference and laying egg number of BPH both on transgenic cry1Ab rice and transgenic SCK rice were not significantly different from those on their controls, while their total number of probing wound caused by PBH expect for feeding on B1 plants was markedly more than that on the control. In contrast, under the non selection condition, total number of probing wound caused by BPH on either transgenic cry1Ab rice or transgenic SCK rice was pronouncedly more than those on their controls. Conversely, their honeydew amount excreted by BPH after feeding for 24 h was significantly less than those on the control. As a conclusion, three tested transgenic rice genotypes with insect resistance acted adverse effect on BHP feeding, and no marked effect on BPH oviposition.

Emergence,Mating and Oviposition Behavior of the Chinese Population in Pink Bollworm,Pectinophora gossypiella (Lepidoptera:Gelechiidae)

The pink bollworm, Pectinophora gossypiella （Lepidoptera： Gelechiidae） is one of the most serious lepidopteran pests of cotton in the world. This pest invaded China at the onset of the 20th century, possibly through repeated introductions from several different locations worldwide. In this paper, we describe different behavioral parameters of this Hubei P. gossypiella strain under laboratory and field conditions. Using an infra-red video recorder, we observed （nocturnal） emergence, flight and mating activities, and oviposition patterns. Moth emergence started from 13：00 and continued up till 23：00. Under laboratory and field conditions, 2-7-d-old moths initiated flight around sunset, peaked 50 rain later and gradually declined until 04：00. Although mating started immediately after darkness （i.e., 20：00）, mating behavior was most intense from 23：00 to 03：40. Oviposition also showed distinct time-related patterns, with approx. 70% eggs laid between 20：00 and 22：00. In the studies of the relationship between flight and oviposition, the duration of flight had an effect on oviposition. The 1-d-old moths flown for 6 and 12 h began oviposition earlier than the unflown ones, and the 6-h flight had no effect on the egg production. However, the longevity of the flown moths was shortened after flight. In addition, the peaks of oviposition for the flown moths were advanced 2-3 d. The age when the moths flied affected the oviposition of adult moths. The earlier the moths started to fly after emergence, the greater the fecundity they had. The average egg production of moths flown for 24 h was less than that of non-flown moths which were of the same age. Both flight and delay in mating could advance the oviposition peak. Our study provides detailed insights in nocturnal activities and the reproductive biology of local P. gossypiella populations, which could be employed to fine-tune current pest management programs in China.

Ovipositional responses of Spodoptera frugiperda on host plants provide a basis for using Bt-transgenic maize as trap crop in China

Spodoptera frugiperda,the pest fall armyworm(FAW),is widespread in more than 100 countries.To date,planting insectresistant transgenic crops is one of the main control methods in its native countries.In this study we evaluated Bt-transgenic maize(Bt maize)and non-transgenic(conventional)maize and six other host plants in greenhouse pot experiments and field trials for oviposition preference by the Chinese populations of FAW.In laboratory trials,female moths preferred to oviposit on maize with no significant preference between conventional and Bt maize.However,after conventional and transgenic maize were exposed to FAW larvae and damaged,oviposition was significantly higher on transgenic maize than on the conventional one.Field trials showed that for plants less damaged at an early stage(seedling stage),oviposition of FAW on transgenic and conventional maize was significantly higher than that on wheat,sorghum,foxtail millet,peanut and soybean while showing no significant difference between transgenic or conventional maize.FAW adults mainly laid eggs on Bt maize,while the larval density and leaf damage rating or percentage of damaged plants were significantly lower than on conventional maize.Larval density and its damage on conventional maize were significantly higher than that on Bt maize and the other five hosts.Thus,maize is a highly preferred and suitable host for S.frugiperda feeding and ovipositing,and Bt maize can be used as trap crop to protect other crops.

Toxicity of several botanical essential oils and their combinations against females of Aedes albopictus(Skuse) and Anopheles minimus(Theobald): Oviposition deterrent, ovicidal and adulticidal efficacies

Objective: To investigate the efficacies of 12 essential oil(EO) formulations from three Zingiberaceae plants(Alpinia galanga, Curcuma zedoaria, and Zingiber cassumunar) individually and in combination with an augmenting Eucalyptus globulus(E. globulus) EO against females of Aedes albopictus(Ae. albopictus) and Anopheles minimus(An. minimus). Methods: These formulations were evaluated for their ovicidal, oviposition deterrent and adulticidal activities against Ae. albopictus and An. minimus by a topical method, a double-choice method and a WHO susceptibility test, respectively. Results: It was found that all formulations of Zingiberaceae plants EOs augmented with E. globulus EO were more effective in oviposition deterrent, ovicidal, and adulticidal activities against the two mosquito species than all of the formulations used without E. globulus EO. Their oviposition deterrent, ovicidal and adulticidal activities were equivalent to those of 10% w/v cypermethrin. In contrast, 70% v/v ethyl alcohol as a control alone was not effective at all. The highest synergistic effect in effective repellency against Ae. albopictus was achieved by 5% Alpinia galanga EO + 5% E. globulus EO and against An. minimus was 5% Zingiber cassumunar EO + 5% E. globulus EO. Moreover, the highest synergistic effects in ovicidal activities against Ae. albopictus and An. minimus were achieved by 10% Zingiber cassumunar EO + 10% E. globulus EO and 5% Curcuma zedoaria EO + 5% E. globulus EO, respectively. For the adulticidal activities, the highest synergistic effect against two mosquitoes was achieved by 5% Curcuma zedoaria EO + 5% E. globulus EO. Conclusions: These results suggest that Zingiberaceae plant EOs augmented with E. globulus EO have a high potential to be developed into oviposition deterrent, ovicidal, and adulticidal agents for controlling populations of Ae. albopictus and An. minimus.

Effects of Various Degrees of Antennal Ablation on Mating and Oviposition Preferences of the Diamondback Moth,Plutella xylostella L.

Using scanning electron microscopy, we investigated the distribution of the trichoid, basiconic, and coeloconic sensilla on the antennae of the diamondback moth （DBM;Plutella xylostella）. The trichoid sensilla were the most abundant sensory organ, and the male moth antennae host signiifcantly more trichoid sensilla than female moth antennae. Conversely, basiconic and coeloconic sensilla were found more frequently on female than on male antennae. We performed experiments with various degrees of antennal ablation and demonstrated that DBM antennae played a key role in the control of mating and oviposition. We found that neither oviposition preference nor mating behaviors changed signiifcantly when less than 1/4 of both antennae were removed. However, there was a signiifcant behavioral change when the antennae were ablated by more than half. As the length of the antenna was shortened, the successful mating rate decreased and mating peak was delayed. An otherwise consistent host preference for oviposition was eliminated when both antennae were completely removed. Furthermore, we found that the number of trichoid sensilla was positively correlated with mating rate and oviposition preference. However, the numbers of basiconic and coeloconic sensilla were not correlated with mating rate and mating peak, but highly correlated with oviposition preference. Taken together, our results indicate that antennal sensory information plays a critical role in the mating and oviposition behaviors of this economically important pest.

Adulticidal, larvicidal, pupicidal and oviposition deterrent activities of essential oil from Zanthoxylum limonella Alston(Rutaceae) against Aedes aegypti(L.) and Culex quinquefasciatus(Say)

Objective: To evaluate adulticidal, larvicidal and oviposition deterrent response of the essential oil from dried Zanthoxylum limonella(Z. limonella) fruit against Aedes aegypti(Ae. aegypti) and Culex quinquefasciatus(Cx. quinquefasciatus).Methods: Z. limonella oil was tested by biological assays at 1%, 5% and 10% concentrations in ethanol. Adulticidal efficacy was tested against the 2–3 day old adult females. Larvicidal activity was tested against immature stage of mosquitoes. Oviposition deterrence of the oil was evaluated on gravid females.Results: The adult mortality was observed after 24 h with the LC50 of 6.0% for Ae.aegypti, and 5.7% for Cx. quinquefasciatus. Larvicidal bioassay was carried out with the 10% Z. limonella oil against immature stages of Ae. aegypti and Cx. quinquefasciatus,which caused 100% mortality after 12 h and 24 h. In the larvicidal experiment,Z. limonella showed effective result at 1%, 5% and 10% concentrations with the values of LT50 Ae. aegypti = 9.78, 5.61, 0.24 h for larvae and LT50= 64.08, 21.23 h for pupae;Cx. quinquefasciatus had LT50= 28.46, 20.25, 1.01 h for larvae and LT50= 67.52, 27.96,4.11 h for pupae, respectively. Oviposition deterrence of the oil was evaluated on gravid females. In the study, 10% Z. limonella showed 100% repellency for Ae. aegypti and99.53% for Cx. quinquefasciatus. Likewise, oviposition activity indexes of these oil concentrations were all negative values ranging from–0.89 to-1.00 for Ae. aegypti and–0.64 to–0.99 for Cx. quinquefasciatus. The oviposition activity indexes values revealed that Z. limonella oil has deterrent effect, and it caused a remarkable negative response resulting in very few eggs.Conclusions: This result indicates that Z. limonella oil can be used as an effective adulticide, larvicide and oviposition deterrent against Ae. aegypti and Cx. quinquefasciatus.

The Insect Oviposition Firstly Discovered on the Middle Jurassic Ginkgoales Leaf from Inner Mongolia, China

Although the evidence of insect oviposition on plant organs has been reported from the late Paleozoic to the Miocene, record from the middle Jurassic is still blank. This paper reports a significant evidence of insect oviposition on plant leaf from the middle Jurassic for the first time. The ovipositional scar is distributed on the abaxial surface of Sphenobaiera leaf（Ginkgoales） from the middle Jurassic Daohugou Formation of Inner Mongolia, China. A new ichnospecies Paleoovoidus venustus sp. nov. is described. The scar is elliptic to oval, arranged in longitudinal rows between leaf veins with almost regular distance, with its long axis paralleling to the leaf venation. This discovery adds new information to the morphology of insect endophytic oviposition probably produced by Odonata existed in a terrestrial ecosystem ~165 Ma ago. The new materials also provide important data for the study of insect reproductive biology, plant-insect interaction and coevolution, as well as understanding the paleoclimate and palaeoenvironment during that time in northeast China.

Efficacies of four plant essential oils as larvicide, pupicide and oviposition deterrent agents against dengue fever mosquito, Aedes aegypti Linn.(Diptera: Culicidae)

Objective:To evaluate larvicidal,pupicidal and oviposition deterrent activities of four plant essential oils from Alpinia galanga(L.)Willd rhizome,Anethum graveolens L.(An.graveolens)fruit,Foeniculum vulgare Mill.fruit,and Pimpinella anisum L.fruit against Aedes aegypti(Ae.aegypti).Methods:Four essential oils at 1%,5%and 10%concentrations were assessed for insecticidal activity against larvae and pupae of Ae.aegypti,following the procedure of a dipping method assay.Oviposition deterrent activity of four essential oils was evaluated on gravid female of Ae.aegypti by a dual-choice oviposition bioassay.Results:The results revealed that An.graveolens oil provided the strongest larvicidal activity against Ae.aegypti among four tested plant essential oils with the highest mortality rate of 100%and LC_(50)value of-0.3%.From the pupicidal experiment,An.graveolens also showed the highest toxicity against Ae.aegypti pupae with the highest mortality rate of 100%at 72 h and LC_(50)value of2.9%.In addition,10%An.graveolens had an oviposition deterrent effect against Ae.aegypti with effective repellency of 100%and an oviposition activity index of-1.0.Conclusions:An.graveolens oil has a good potential as a larvicidal,pupicidal and oviposition deterrent agent for controlling Ae.aegypti.

Ovipositional preference and larval performance of poplar defoliator,Clostera restitura on different poplar clones in north-western India

We evaluated ten poplar clones （G-3, G-48, L-50/88, L- 154/84, L-156/89, S7C8, S7C15 WSL-22, WSL-29 and Uday） for ovi- positional preference and larval performance of Clostera restitura. Fe- male moths did not show any preference with respect to clones for ovi- position. Significant differences were observed for number of eggs laid on different plant parts. C. restitura laid eggs in clusters, preferably on upper surface of leaf and size of the egg cluster varied from 15 to 167 eggs. Clones varied for their relative resistance and susceptibility to C. restitura. L-50/88; L-156/89 were identified as most resistant clone based on minimum leaf consumption, whereas S7C15 was found to be most susceptible clone to C. restitura. In multiple choice experiments, no feeding preference by C. restitura larvae was detected amongst different poplar clones. After initial settlement of larvae on a particular clone, the larvae remained confined to that clone and negligible inter-clonal move- ment was noticed subsequently. The fresh pupal weight was correlated negatively （r = -0.37） with percentage surface leaf area eaten and positively （r = 0.47） with length of larval period, measured on different clones. Relationship between percentage leaf area eaten and length of larval period was negative （r = -0.23）. Owing to relative resistance of L- 50/88 and L-156/89 against C. restitura, these clones can be recom- mended for plantation in defoliator prone areas in north-western India.

Oviposition Site Selection of the Plateau Frog (Nanorana pleskei) in the Zoige Wetland, China

For oviparous species, oviposition site selection influences adult reproductive success as well as the fitness of the resulting offspring. Females usually choose potential egg-laying sites depending on abundance and quality to maximize their reproductive success. We focused on the oviposition site selection of this plateau frog in Zoige wetland and investigated how the egg-laying pattern of the females influences their offspring＇s survival. We found that shallow waters, decentralized spawning patterns, and egg attachment to appropriate distance to the water surface were the main spawning strategies of Nanorana pleskei endemic to Qinghai-Tibet Plateau. We argued that drought caused by increasing temperature and variable precipitation has probably influenced N. pleskei reproductive success, which may be a crucial reason for its population decline. Our findings have important significance for habitat preservation, increasing embryo survival and establishing practical conservation policies.

Effects of NaCl stress on the biochemical substances in Bt cotton as well as on the growth and development and adult oviposition selectivity of Helicoverpa armigera

Background:Recently,due to the development of food security strategies,cotton has been planted in inland saline-alkali dry soils or in coastal some saline-alkali soils in China.Under the condition,to comprehensively prevent and control Helicoverpa armigera in cotton fields with saline-alkali soils,it is important to study the larval growth and development of H.armigero and to study adult oviposition selectivity in H.armigera adults that feed on NaCI-stNaCled cotton plants.Results:In this study,Bt cotton GK19 was used for the experimental group and its nontransgenic parent Simian 3 was used for the control to study the effects of biochemical substances in cotton as well as larval growth and development and adult oviposition selectivity of H.armigera.The experiments were performed by growing cotton indoors under NaCl stress at concentrations of 0 mmol-L-1,75 mmol-L-1 and 150 mmol-L-1,respectively.The results showed that the expression of Bt protein was significantly inhibited for NaCI-stressed Bt cotNaClThe content of soluble protein and K+ in the leaves of cotton were decreased,while the content of gossypol and Na+were increased.In addition,the 5th instar H.armigera larvae exhibited shorten the life span in a 13-day trial period.Under enclosure treatments and at different female densities,the adult oviposition of H.armigera decreased on high NaCI-stressed nontransgenic coNaCl,while the oviposition on Bt cotton tended to first increase but then decrease under low,moderate and high NaCl stress treatments.Conclusions:Under certain content ranges of NaCl stress treatments,larval of H.armigera growth and development,and adult oviposition were no significant difference in the change for a certain period.However,under high NaCl stress,larval growth,development and adult oviposition were affected,which may provide insights for the prevention and control of H.armigero for Bt cotton in saline-alkali soils.

Oviposition preference of Anoplophora glabripennis emerging from five host tree species under field conditions

The Asian longhorned beetle （ALB）, Anoplophora glabripennis （Motschulsky） is a polyphagous woodborer of hardwood trees. In order to well understand the oviposition preference of A. glabripennis emerging from different larval host tree species, we selected five common host tree species in the field and evaluated its oviposition preferences. The five host tree species are Acer negundo （AN）, Salix matsudana f. lobato-glandulosa （SM）, Populus nigra L. var. thevestina （Dode） Bean （PN）, P. simonii × P. pyramidalis cv. Opera 8277 （PS） and P. alba var. pyramidalis （PA）. Results show that adult beetles emerging from these five tree species almost have the same oviposition phenomenon. All adult beetles, except those emerging from PS, chewed the highest potential sites and laid most eggs on AN trees. Adult beetles emerging from AN, PN, PS and PA did not chew any sites nor laid any eggs on PA trees. These results showed that adult A. glabripennis emerging from the five host tree species did not show any clear oviposition preference for their larval host tree species in the field but they did present the most obvious preference for AN and the lowest preference for PA.

Toxicity and sub-lethal effect of endemic plants from family Anacardiaceae on oviposition behavior of Aedes albopictus

Objective: To evaluate the lethal concentration, oviposition deterrence and ovicidal activity of acetone extracts of Melanochyla fasciculiflora(M. fasciculiflora) leaf and Gluta renghas(G. renghas) leaf against Aedes albopictus(Ae. albopictus). Methods: To determine the lethal concentration of Anacardiaceae, ten test concentrations of the extracts ranging from 200 to 650 mg/L were selected for larvicidal bioassays and 25 early fourth instar larvae were exposed to the extracts for 24 h. The sub-lethal concentrations used for oviposition deterrence was the value of LC25, LC50 and LC75 from above study which is 235 mg/L, 470 mg/L and 705 mg/L for M. fasciculiflora extract and 187.5 mg/L, 375 mg/L and 562.5 mg/L for G. renghas extract, respectively. Twenty gravid Ae. albopictus were allowed to oviposit in different treated concentrations. For oviciding procedure, a total of 300 eggs of Ae. albopictus were soaked in solution with each treated concentration as mentioned above for 24 h. After 24 h, eggs were sieved and soaked in seasoned water, and hatching rates were calculated. For comparison, only seasoned water was used in control experiment.Results: G. renghas demonstrated lower LC50 value of 372.80 mg/L compared to M. fasciculiflora(467.90 mg/L). The activity index of negative oviposition revealed the deterrent effect and thus, caused a remarkable negative response resulting in oviposition of fewer eggs compared with control(without plant extract). The acetone extract of M. fasciculiflora was more effective than G. renghas extract in displaying oviposition deterrence potential since the latter did not possess the deterring effect within the concentration range tested. However, both plant extracts exhibited excellent oviciding effect as 92.33% of eggs failed to be hatched when treated with 705.0 mg/L of M. fasciculiflora and 86.67% with 562.5 mg/L of G. renghas. The oviposition deterrence and percentage of egg mortality were directly proportional to the concentrations of extracts in both plants tested. Conclusions: These results clearly indicate that the acetone extract of G. renghas could be served as potential larvicide, whereas M. fasciculiflora has better sub-lethal effect for oviposition deterrence and against Ae. albopictus as an oviciding agent.

Oviposition Site Selection in the Malayan Giant Frog (Limnonectes blythii) in Singapore: Conservation Implications

Amphibians require specific habitats for breeding and loss or degradation of such habitats can negatively affect reproductive success. Oviposition site selection within a habitat is also important as site quality is linked to larval survivorship and metamorphic success. We investigated oviposition site preferences of the stream-breeding frog Limnonectes blythii in Singapore through surveys and habitat measurements of breeding and non-breeding sites（N = 30 and 32, respectively）. The study species L. blythii is classified as Near Threatened（NT） in the IUCN red list and is associated with medium sized forest streams. L. blythii appeared to prefer streams with higher water p H and shallower water depths for oviposition. Our findings have implications in conservation management as it provides the baseline for habitat restoration for creation of new and for preserving existing breeding habitat of L. blythii.

Oviposition Site Preference and Its Effects on Subsequent Development of Variegated Grasshopper (Zonocerus variegatus L.) under Laboratory Conditions

Female grasshoppers can affect the fitness of their offspring through their selection of oviposition site. Knowledge of soil type on oviposition, and its effects on subsequent development can provide guidelines for habitat manipulations that reduce the harmful effects of these pests on farmers fields. The influence of soil types on the oviposition site preference of variegated grasshopper (Zonocerus variegatus L.) reared some cassava (Manihot esculenta Crantz) varieties, was investigated in a cage trial carried out at the Bio factory laboratory, School of Agriculture and Food Sciences, Njala University, Sierra Leone during 2022/2023. The treatments comprised three soil types (Sandy, Loamy and Clay), each with three replications laid out in a randomized complete block design (RCBD) in wooden cages. Data were collected on the following development parameters including, Net reproductive growth ratio (R0), Generation time (Tc), Intrinsic rate of increase (rm), Finite rate of increase (), Doubling time (Dt), and overall survivorship. Findings revealed that, Z. variegatus L. preferred sandy soil in which, on average, most eggs were deposited (338, 6.62 4.40), followed by loamy soil, 286 (5.53 3.96), and then, clayey soil, 200 (3.91 3.85);though, the differences were not significant. This study established that Z. variegatus deposited more eggs in sandy soil > loamy soil > clayey soil, respectively;and subsequent survivorship of the immature unto mature adult insect, revealed a similar order. This indicates that the sandy soil is the most preferred substrate for oviposition and subsequent development into adult insects.

Repellent effects of pongam oil on settlement and oviposition of the common greenhouse whitefly Trialeurodes vaporariorum on chrysanthemum

The repellent activities, including host deterrence and anti-oviposion, of pongam oil against the adults of the common greenhouse whitefly Trialeurodes vaporariorum Westwood in greenhouses were tested. Chrysanthemum plants treated with different concentrations （0.5%-2.0%） of water-suspended pongam oil showed relatively long-lasting host deterrent and anti-oviposition effects on the adults of greenhouse whitefly. Although the repellent effect declined in time and concentration, strong effects on the reduction of oviposition were found, which lasts, dependent on concentration at least 12 days after application.

Differential responses to artificial selection on oviposition site preferences in Drosophila melanogaster and D. simulans

The preference-performance relationship in plant-insect interactions is a cen- tral theme in evolutionary ecology. Among many insects, eggs are vulnerable and larvae have limited mobility, making the choice of an appropriate oviposition site one of the most important decisions for a female. We investigated the evolution of oviposition preferences in Drosophila melanogaster Meigen and Drosophila simulans Sturtevant by artificially selecting for the preference for 2 natural resources, grape and quince. The main finding of our study is the differential responses of D. melanogaster and D. simulans. Although preferences evolved in the experimental populations of D. melanogaster, responses were not consistent with the selection regimes applied. In contrast, responses in D. simulans were consistent with expectations, demonstrating that this species has selectable genetic variation for the trait. Furthermore, crosses between D. simulans divergent lines showed that the genetic factors involved in grape preference appear to be largely recessive. In summary, our artificial selection study suggests that D. melanogaster and D. simulans possess different genetic architectures for this trait.

Effects of seed type and bruchid genotype on the performance and oviposition behavior of Zabrotes subfasciatus （Coleoptera： Bruchidae）

The effect of different bean varieties on the performance of the bruchid beetle Zabrotes subfasciatus Boheman （Coleoptera： Bruchidae）, was determined by using wild and cultivated seeds of the genus Phaseolus. Results showed that the quality of the host plant affected the performance and the oviposition behavior of female beetles. Overall, bruchid performance was higher on cultivated seeds than on wild seeds. It was also found that the oviposition behavior and the performance of their offspring differed between females that originated from wild versus cultivated seeds. We also demonstrated the importance of a genetic component in bruchid performance： longevity, fecundity, larval development, adult size, and the sex ratio of the progeny varied according to their matemal lineage （‘family＇ ）. For example, on the same host type, some females laid twice as many eggs as females from other‘families＇, and the sex ratio among the offspring correlated with that of their mother. Thus, the performance and behavior of Z. subfasciatus are not only affected by environmental factors such as the quality of the seeds on which they develop, but also have a genetic basis which can counterbalance a less suitable quality of the host plant. For a crop pest such as Z. subfasciatus, its ability to survive and adapt on host plants of differing quality may be an important attribute to consider for pest management.