01617nas a2200193   4500008004100000020001400041245010900055210006900164260001000233300001000243490000700253520092900260653002201189100002201211700002101233700002101254700001901275856012901294       2011                        eng d  a1612-475800aPre-exposure to sex pheromone did not affect mating behavior in the sweetpotato weevil Cylas formicarius0 aPreexposure to sex pheromone did not affect mating behavior in t  cMarch  a93-970 v843 aIn sterile insect technique (SIT) programs, the released sterile males are important for their effectiveness. The use of sex pheromones to collect males is economical; however, pre-exposure to sex pheromones may affect male mating behavior, and would thus reduce the effectiveness of the SIT programs. Males exposed to sex pheromone may become attractive to other males due to pheromone adsorption on their body impregnation, prevent mating and reduce the dispersal of sterile males. We examined the effect of pre-exposure to sex pheromone on the mating behavior of male sweetpotato weevil Cylas formicarius. Pre-exposure to high-dose sex pheromone for 24 h did not affect the male mating behavior of C. formicarius, and the exposed males did not attract other males. These results suggest that male C. formicarius that were collected from a mass-rearing facility using sex pheromone can be effectively used in SIT programs.10aCylas formicarius1 aKuriwada, Takashi1 aKumano, Norikuni1 aShiromoto, Keiko1 aHaraguchi, Dai  uhttps://weevil.myspecies.info/pre-exposure-sex-pheromone-did-not-affect-mating-behavior-sweetpotato-weevil-cylas-formicarius01528nas a2200193   4500008004100000020001400041245009500055210006900150260000900219300001000228490000700238520086900245653002701114100002201141700002101163700002101184700001901205856011001224       2011                        eng d  a0021-491400aSimplification of the collecting method of adult sweetpotato weevils from artificial diets0 aSimplification of the collecting method of adult sweetpotato wee  c2011  a22-240 v553 aThe West Indian sweetpotato weevil Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae) is a major pest of the sweet potato Ipomoea batatas (L.) Lam (Solanales: Convolvulaceae) in some countries. In order to improve the mass-rearing systems involved in an eradication program employing the sterile insect technique (SIT), we improved the efficiency of the method used for collecting adult weevils from artificial larval diets; this was done by using the combination of a sieve and Tullgren apparatus. Using this combination, we could collect 95.4% of weevils from artificial diets. Furthermore, the time spent in collection with this method was approximately one-fifth of that spent with the existing hand-sorting method. These results showed that this new collection method will improve the efficiency of mass rearing of West Indian sweetpotato weevils.10aEuscepes postfasciatus1 aKuriwada, Takashi1 aKumano, Norikuni1 aShiromoto, Keiko1 aHaraguchi, Dai  uhttps://weevil.myspecies.info/simplification-collecting-method-adult-sweetpotato-weevils-artificial-diets01385nas a2200193   4500008004100000020001400041245013600055210006900191260000900260300001000269490000700279520066000286653002700946100002200973700002100995700002101016700001901037856013501056       2011                        eng d  a0021-491400aThe effect of an artificial adult diet on the reproductive performance of the West Indian sweetpotato weevil Euscepes postfasciatus0 aeffect of an artificial adult diet on the reproductive performan  c2011  a27-290 v553 aThe West Indian sweetpotato weevil Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae) is a major pest of the sweet potato Ipomoea batatas (L.) Lam (Solanales: Convolvulaceae) in some countries. To improve mass rearing systems involved in an eradication program employing the sterile insect technique (SIT), we examined the effect of an artificial adult diet on the reproductive performance of both male and female E. postfasciatus. The artificial diet had a negative effect on female fecundity but no effect on male mating ability. Our results suggest that the artificial diet should be improved to prevent adverse effects on female fecundity.10aEuscepes postfasciatus1 aKuriwada, Takashi1 aKumano, Norikuni1 aShiromoto, Keiko1 aHaraguchi, Dai  uhttps://weevil.myspecies.info/effect-artificial-adult-diet-reproductive-performance-west-indian-sweetpotato-weevil-euscepes-postfa01584nas a2200193   4500008004100000020001400041245010100055210006900156260000800225300001200233490000700245520091200252653002201164100002201186700002101208700002101229700001901250856012101269       2011                        eng d  a0307-696200aAge-dependent investment in death-feigning behaviour in the sweetpotato weevil Cylas formicarius0 aAgedependent investment in deathfeigning behaviour in the sweetp  cJun  a149-1540 v363 aBecause life-history theory predicts that risky behaviours such as mating should increase as life expectancy decreases, predatory avoidance is expected to decrease with age. However, this prediction has not been examined. In the present study, the effect of age on death-feigning behaviour, a form of predatory avoidance behaviour in the sweetpotato weevil Cylas formicarius (Summers) (Coleoptera: Brentidae), is investigated by performing a longitudinal study. Because the effects of mating history and age usually cannot be distinguished, mating history is controlled. The results show that only female weevils decrease the investment in death-feigning behaviour with age, whereas male weevils do not show any age-related change. In addition, death-feigning behaviour of mated females is longer than that of virgin females, possibly because additional mating partners would be not needed by mated females.10aCylas formicarius1 aKuriwada, Takashi1 aKumano, Norikuni1 aShiromoto, Keiko1 aHaraguchi, Dai  uhttps://weevil.myspecies.info/age-dependent-investment-death-feigning-behaviour-sweetpotato-weevil-cylas-formicarius01746nas a2200193   4500008004100000020001400041245012600055210006900181260001000250300001000260490000700270520103500277653002201312100002201334700002101356700002101377700001901398856013501417       2010                        eng d  a0015-404000aEFFECT OF IRRADIATION ON DEATH-FEIGNING BEHAVIOR IN THE MALE SWEETPOTATO WEEVIL CYLAS FORMICARIUS (COLEOPTERA: BLENTIDAE)0 aEFFECT OF IRRADIATION ON DEATHFEIGNING BEHAVIOR IN THE MALE SWEE  cMarch  a39-440 v933 aThe sterile insect technique (SIT) is widely used to suppress or eradicate target insect pest populations. The effectiveness of SIT depends on the ability of the released sterile males to mate with and inseminate wild females. Irradiation is effective for sterilizing mass-reared insects, and the negative impacts of this procedure are not limited to reproductive cell damage. In this study, we evaluated the death-feigning that is considered as an antipredator behavior of male Cylas formicarius (Summers) (Coleoptera: Blentidae) irradiated with 200 Gy, which is the dose used in the SIT program in Okinawa Prefecture. Irradiated male insects were observed in the laboratory for 10 d after irradiation. On d 0, fewer irradiated males feigned death than nonirradiated males. The number of irradiated and nonirradiated males who feigned death and the duration of their death-feigning were about the same from 2 d after irradiation. On the basis of our results, we discuss the optimal release time of irradiated male C. formicarius.10aCylas formicarius1 aKuriwada, Takashi1 aKumano, Norikuni1 aShiromoto, Keiko1 aHaraguchi, Dai  uhttps://weevil.myspecies.info/effect-irradiation-death-feigning-behavior-male-sweetpotato-weevil-cylas-formicarius-coleoptera-blen01856nas a2200193   4500008004100000020001400041245010700055210006900162260001400231300001200245490000800257520116300265653002701428100002201455700002101477700002101498700001901519856012401538       2011                        eng d  a0179-161300aThe Effect of Inbreeding on Mating Behaviour of West Indian Sweet Potato Weevil Euscepes postfasciatus0 aEffect of Inbreeding on Mating Behaviour of West Indian Sweet Po  cSeptember  a822-8280 v1173 aWhen there is an inbreeding depression, mating with a kin individual is generally considered maladaptive behaviour. However, in some conditions, the inclusive fitness benefits from inbreeding may outweigh the costs of inbreeding depression, and thus, inbreeding tolerance is often adaptive. Inbreeding depression and the effect of relatedness on mating behaviour in the West Indian sweet potato weevil Euscepes postfasciatus were examined. No significant inbreeding depression was detected as indicated by body weight and number of progeny emerging from sweet potato roots. Male mating performance (i.e. number of mating occurrences per night) was adversely affected by inbreeding depression, but the effect was low (fitness loss was 6.3%). Although there were no significant differences in latency to mounting, pre-copulatory guarding, copulation and post-copulatory guarding duration between full-sib and non-kin pairs, the copulation rate of full-sib pairs was significantly higher than that of non-kin pairs. These results support the theoretical prediction that when inbreeding depression is weak, copulation with close relative individuals is favoured.10aEuscepes postfasciatus1 aKuriwada, Takashi1 aKumano, Norikuni1 aShiromoto, Keiko1 aHaraguchi, Dai  uhttps://weevil.myspecies.info/effect-inbreeding-mating-behaviour-west-indian-sweet-potato-weevil-euscepes-postfasciatus02071nas a2200193   4500008004100000020001400041245013300055210006900188260000900257300001400266490000700280520135000287653002201637100002201659700002101681700002101702700001901723856013501742       2011                        eng d  a0340-544300aInbreeding avoidance or tolerance? Comparison of mating behavior between mass-reared and wild strains of the sweet potato weevil0 aInbreeding avoidance or tolerance Comparison of mating behavior   cJuly  a1483-14890 v653 aInadvertent selection is an important genetic process that frequently occurs during laboratory culture. The mass-reared strain of the sweet potato weevil Cylas formicarius exhibits stronger inbreeding depression than the wild strain does. When inbreeding depression occurs in a population, mating with a close relative is often considered maladaptive; however, in some contexts, the inclusive fitness benefits of inbreeding may outweigh the costs, favoring individuals that tolerate a low level of inbreeding depression. Theory predicts that mass-reared strain weevils will avoid inbreeding while wild strain weevils will tolerate inbreeding. To examine this prediction, we compared the effect of relatedness on the mating and insemination successes in mass-reared and wild strains of C. formicarius. While close relative pairs of the wild strain copulated less frequently than non-kin pairs, almost all mass-reared strain pairs copulated irrespective of relatedness. The results showed that the strain with weak inbreeding depression (wild strain) avoided inbreeding, whereas the strain with strong inbreeding depression (mass-reared strain) tolerated inbreeding. The contradiction between the theoretical prediction and our results is discussed from the perspective of laboratory adaptation, mating systems, and life history of C. formicarius.10aCylas formicarius1 aKuriwada, Takashi1 aKumano, Norikuni1 aShiromoto, Keiko1 aHaraguchi, Dai  uhttps://weevil.myspecies.info/inbreeding-avoidance-or-tolerance-comparison-mating-behavior-between-mass-reared-and-wild-strains-sw01741nas a2200181   4500008004100000020001400041245010900055210006900164260001300233300001400246490000700260520108500267100002201352700002101374700002101395700001901416856012401435       2009                        eng d  a0003-347200aCopulation reduces the duration of death-feigning behaviour in the sweetpotato weevil, Cylas formicarius0 aCopulation reduces the duration of deathfeigning behaviour in th  cNovember  a1145-11510 v783 aAlthough there have been numerous studies on the effects of mating history on mating behaviour, few studies have reported the relationship between mating history and other contextual behaviours such as foraging and predator avoidance. We examined the effect of mating history on death-feigning behaviour (an antipredator behaviour) in the sweetpotato weevil. Because mating behaviour can be divided into phases, we examined the effects of encounters with the opposite sex, copulation and insemination success on death-feigning behaviour. For females after copulation and males after multiple copulations the duration of death-feigning behaviour was reduced, whereas encounters with the opposite sex had no effect. Insemination success did not affect the duration of death feigning in males, but inseminated females reduced the duration of death feigning. We discuss the implications of these results for the effect of mating history on this antipredator behaviour. [copyright] 2009 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.1 aKuriwada, Takashi1 aKumano, Norikuni1 aShiromoto, Keiko1 aHaraguchi, Dai  uhttps://weevil.myspecies.info/copulation-reduces-duration-death-feigning-behaviour-sweetpotato-weevil-cylas-formicarius01885nas a2200193   4500008004100000020001400041245014100055210006900196260000900265300001200274490000700286520115300293653002701446100002201473700002101495700002101516700001901537856013501556       2009                        eng d  a0015-404000aHigh population density and egg cannibalism reduces the efficiency of mass-rearing in Euscepes postfasciatus (Coleoptera: Curculionidae)0 aHigh population density and egg cannibalism reduces the efficien  cJune  a221-2280 v923 aThe West Indian sweetpotato weevil Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae) is a major pest of sweetpotato Ipomoea batatas (L.) Lam (Solanales: Convolvulaceae) in some countries. In order to improve mass-rearing for an eradication program employing the sterile insect technique (SIT), optimal population density of E. postfasciatus in an artificial diet was examined. Six population densities (1000, 4000, 7000, 10000, 13000, and 16000 individuals per container with 200 g of artificial diet) were compared for effect on the number of eggs collected and hatchability. The total number of eggs collected after 24 d increased with an increase in population density and reached a saturation level at 13,000 individuals, whereas hatchability was not affected by population density. The results indicated that optimal population density in mass rearing was 13,000 individuals on 200 g of artificial diet. Furthermore, we examined cannibalism by adult weevils in the presence of other diets . The result suggested that egg cannibalism may be a major reason for the low rate of egg collection in the mass rearing of E. postfasciatus.10aEuscepes postfasciatus1 aKuriwada, Takashi1 aKumano, Norikuni1 aShiromoto, Keiko1 aHaraguchi, Dai  uhttps://weevil.myspecies.info/high-population-density-and-egg-cannibalism-reduces-efficiency-mass-rearing-euscepes-postfasciatus-c02140nas a2200205   4500008004100000020001400041245013700055210006900192260000800261300001000269490000800279520138300287653002701670100002101697700002201718700002101740700001901761700001901780856013501799       2010                        eng d  a0013-870300aEvaluation of partial sterility in mating performance and reproduction of the West Indian sweetpotato weevil, Euscepes postfasciatus0 aEvaluation of partial sterility in mating performance and reprod  cJul  a45-520 v1363 aThe sterile insect technique (SIT) is based on population and behavioral ecology and is widely used to suppress or eradicate target pest insect populations. The effectiveness of SIT depends on the ability of the released sterile males to mate with and inseminate wild females. The use of gamma-radiation to induce sterility is, however, associated with negative impacts not only on reproductive cells but also on somatic cells. Consequently, irradiation for sterilization diminishes mating performance over time. In this study, we evaluated the balance between the irradiation dose and both fertility and mating propensity in Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae) for 22 days following irradiation. The mating propensity of males irradiated with a 150-Gy dose, as currently used to induce complete sterility of E. postfasciatus in the SIT program in Okinawa Prefecture, was equal to that of non-irradiated weevils for up to 6 days, and the mating propensity of males irradiated with a dose of 125 Gy was equal to that of non-irradiated weevils for twice this period (12 days). The fertilization ability of weevils irradiated with a dose of 125 Gy was reduced by 4.6% in males and 0.6% in females, compared to the potential fertilization ability. We also discuss the possibility of the application of partially sterilized insects in eradication programs.10aEuscepes postfasciatus1 aKumano, Norikuni1 aKuriwada, Takashi1 aShiromoto, Keiko1 aHaraguchi, Dai1 aKohama, Tsuguo  uhttps://weevil.myspecies.info/evaluation-partial-sterility-mating-performance-and-reproduction-west-indian-sweetpotato-weevil-eusc02074nas a2200205   4500008004100000020001400041245013500055210006900190260000800259300001200267490000800279520131700287653002701604100002101631700002201652700002101674700001901695700001901714856013501733       2010                        eng d  a0013-870300aEffect of body size and sex ratio on male alternative mating tactics of the West Indian sweetpotato weevil, Euscepes postfasciatus0 aEffect of body size and sex ratio on male alternative mating tac  cMay  a154-1610 v1353 aMale body size is considered to be one of the major determinants of mating success among many insect species. Because the effectiveness of the sterile insect technique (SIT) depends on the ability of released sterile males to mate with and inseminate wild females, it is indispensable to understand the effect of male body size on the mating behavior of both sexes for the progress of the SIT program. We investigated how male body size and the presence of other rival males affect the guarding and copulatory durations of the West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae). In this species, males guard females before and after copulation. By observing the mating behavior under two sex-ratio conditions (male-to-female ratios of 1:1 and 2:1), we found that small males hastened to court females when rival males were present, but the females rejected these small males as mates. Therefore, we consider that female weevils adopt a counter-adaptation for mate preference in response to this male mating strategy. Body size did not affect the durations of copulation and post-copulatory guarding. Although we found a conditional mating strategy for body size in E. postfasciatus, it is unlikely to have a large influence on the weevil-eradication program using SIT.10aEuscepes postfasciatus1 aKumano, Norikuni1 aKuriwada, Takashi1 aShiromoto, Keiko1 aHaraguchi, Dai1 aKohama, Tsuguo  uhttps://weevil.myspecies.info/effect-body-size-and-sex-ratio-male-alternative-mating-tactics-west-indian-sweetpotato-weevil-euscep01979nas a2200205   4500008004100000020001400041245014500055210006900200260001200269300001200281490000700293520120900300653002701509100002101536700002201557700002101579700001901600700001901619856013501638       2011                        eng d  a1438-389600aIntensive resistance by females before copulation induces insemination failure in the West Indian sweet potato weevil Euscepes postfasciatus0 aIntensive resistance by females before copulation induces insemi  cJanuary  a111-1170 v533 aPersistent mating attempts by males (sexual harassment) are frequently observed among animals. For females, resisting persistent males can be costly because vigorous resistance increases both energy expenditure and the possibility of injury. Although one tactic for coping with male harassment is to cease resistance and mate with the persistent partner, the females of several species are able to prevent the fertilization of their egg(s) despite copulation. In this study, we used three different sex ratios to investigate whether a male's mating persistence affects his mating success in the West Indian sweet potato weevil Euscepes postfasciatus, in which males mount females both before and after copulation. Consistent with our predictions, we found that female weevils resist and manipulate sperm transfer either before or during copulation according to their preferences. Female weevils were able to reject the sperm of persistent males despite having copu- lated with them. However, neither copulation and/or post-copulatory mounting affected insemination success. We speculate that the intensive resistance shown by females before copulation may induce mechanical sterility in E. postfasciatus.10aEuscepes postfasciatus1 aKumano, Norikuni1 aKuriwada, Takashi1 aShoromoto, Keiko1 aHaraguchi, Dai1 aKohama, Tsuguo  uhttps://weevil.myspecies.info/intensive-resistance-females-copulation-induces-insemination-failure-west-indian-sweet-potato-weevil01801nas a2200229   4500008004100000020001400041245015500055210006900210260001300279300001200292490000800304520095200312653002701264100002101291700001801312700002201330700002101352700001901373700002501392700001901417856013501436       2010                        eng d  a0022-201100aThe neogregarine protozoan Farinocystis sp. reduces longevity and fecundity in the West Indian sweet potato weevil, Euscepes postfasciatus (Fairmaire)0 aneogregarine protozoan Farinocystis sp reduces longevity and fec  cNovember  a298-3040 v1053 aThe number of West Indian sweet potato weevils, Euscepes postfasciatus, being mass-reared in a facility for use in sterile insect technique (SIT) eradication programs has undergone a drastic reduction. A neogregarine protozoan pathogen Farinocystis sp. (an undescribed species) was detected in vivo in the mass-reared E. postfasciatus. We investigated the effects of this disease on the longevity and fecundity of host weevils and the incubation time of the disease in the host body under mass-rearing conditions. Our results demonstrated that infection by this Farinocystis sp. decreased both longevity and fecundity in E. postfasciatus. In particular, the pathogen severely limited the production of progeny by infected females compared to healthy females. Therefore, we consider this protozoan infection to be the major cause of the decreased E. postfasciatus production in the mass-rearing facility. (C) 2010 Elsevier Inc. All rights reserved.10aEuscepes postfasciatus1 aKumano, Norikuni1 aIwata, Noriko1 aKuriwada, Takashi1 aShiromoto, Keiko1 aHaraguchi, Dai1 aYasunaga-Aoki, Chisa1 aKohama, Tsuguo  uhttps://weevil.myspecies.info/neogregarine-protozoan-farinocystis-sp-reduces-longevity-and-fecundity-west-indian-sweet-potato-weev