Potential host fruits for Drosophila suzukii: olfactory and oviposition preferences and suitability for development

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), the spotted wing drosophila, is a pest endemic to Southeast Asia that invaded the Americas and Europe in 2008. In contrast to most of its congeners, D. suzukii possesses a serrated ovipositor that allows it to lay eggs in unwounded commercial fruits, resulting in severe revenue losses for the industry. The purpose of this study was to determine the susceptibility of known host fruits, including cherry, strawberry, blueberry, and grape, and potential host fruits, such as banana and apple, to attack by D. suzukii. Based on the responses to volatile cues offered in a six‐choice olfactometer, the preference of female D. suzukii was ranked in the following order: strawberry = cherry > banana = apple = blueberry = grape, but in no‐choice and choice oviposition tests, the preferences were ranked as follows: cherry > strawberry = blueberry > grape = banana > apple. Furthermore, we reconfirmed that D. suzukii mainly targets rotten fruit for feeding and ripe fruit for oviposition, and females preferred fruits with intensive mechanical damage. Based on developmental parameters, apple was the least suitable host. This study has implications for the control of D. suzukii, especially in mixed fruit orchards, by providing a promising avenue for exploiting behaviour‐based control tools and emphasizing the importance of phenology in host fruit susceptibility.     

Apple maggot fly response to red sphere traps in relation to fly age and experience

Responses of the apple maggot fly,Rhagoletis pomonella (Walsh), to 8 cm red sticky sphere traps, baited with the synthetic fruit odor butyl hexanoate, were investigated in field-caged apple trees containing green or red Gravenstein apples. Trap capture rate and the probability of oviposition in apples before capture generally increased with female age and number of mature eggs in ovaries. Two days of pre-test exposure of mature females to red hawthorns, green Red Delicious apples or green Gravenstein apples had no significant effect on the likelihood of a fly finding a red sphere. However, before capture on a sphere or departing a tree, hawthorn-exposed females found significantly fewer apples and laid significantly fewer eggs than females exposed to Gravenstein apples. Variation in duration of pre-test exposure (1–4 days) of flies to Gravenstein apples had no detectable influence on female response to apples or to a red sphere in a test tree. The relevance of these findings to effectiveness of sphere traps, forR. pomonella control in commercial orchards is discussed.     

Oviposition preference of Anthocoris nemorum and A. nemoralis for apple and pear

Anthocoris nemorum L. and Anthocoris nemoralis Fabricius (Heteroptera: Anthocoridae) are important predators of insect pests in pome fruit. Females insert their eggs in leaf tissue. The females’ choice of oviposition site is important for the subsequent distribution of nymphs on host plants. Oviposition preference for apple and pear leaves was tested in the laboratory in four experiments (experiments 1–4). In three experiments it was tested whether simulated insect damage to leaves (experiments 5 and 6) or the presence of prey (experiment 7) influenced oviposition preference. The effect of the presence of prey was only tested for A. nemorum on apple leaves. There was a highly significant anthocorid species × plant interaction for the number of eggs laid on apple and pear leaves. Anthocoris nemorum laid more eggs on apple than on pear leaves, while A. nemoralis preferred pear. Anthocoris nemorum's preference for apple increased over the 6‐week period in which experiments 1–4 were performed, from 66% to 91% eggs laid on apple leaves. No change over time in preference was found for A. nemoralis. Across experiments 1–4, the majority of A. nemorum eggs were laid near leaf margins, whereas eggs of A. nemoralis were more commonly found in the leaf centre, 5 mm or more from the margin, with a highly significant leaf region × species interaction. There was no significant difference in preference for leaf side between A. nemorum and A. nemoralis, but there was a highly significant plant × leaf side × experiment interaction. Thus, more eggs were laid on the ventral than on the dorsal side of pear leaves in experiment 4, while significantly more eggs were laid on the dorsal side of apple leaves in experiments 3 and 4. Choice tests between damaged and healthy leaves showed that A. nemorum laid significantly more eggs on the damaged leaves, while A. nemoralis preferred healthy leaves. Anthocoris nemorum showed a near‐significant preference for ovipositing on leaves with eggs of Operophtera brumata (Lepidoptera: Geometridae). The oviposition preferences found correspond to the natural distribution of these predators in apple and pear orchards. The preference of A. nemorum for leaf margins, and of A. nemoralis for the leaf centre as an oviposition site, supports earlier observations. A preference for leaf side for oviposition site has not been reported earlier. Preference for damaged leaves could help A. nemorum to locate prey in a field situation.     

Western corn rootworm (Diabrotica virgifera virgifera LeConte) (Coleoptera: Chrysomelidae) oviposition can be released by decapitation

Nervous system control of western corn rootworm (Diabrotica virgifera virgifera LeConte, WCR) (Coleoptera: Chrysomelidae) oviposition was studied using decapitation. Gravid females (n = 364) were decapitated with scissors and floated in water-filled Petri dishes. Oviposition by individuals was observed at 30 min intervals for 4 hr after decapitation; cumulative oviposition was tallied at 48 hr post-treatment. Overall, 82.7% of females laid eggs within 48 hr. Oviposition commenced quickly; 78.4% of females laid eggs during the observation period, 81.8% of these began egg laying within 30 min of decapitation. Egg-laying females deposited a total of 66.8 ± 2.1 eggs (mean ± SEM); this was 85.1% of the total mature egg load. Dissection revealed that 31.9% of n = 301 laying females and 14.3% of 63 non-laying females had a rupture of the common oviduct, manifest as an egg-filled hernia containing a mean of 8.17 ± 1.3 eggs (range: 1–83). Among n = 237 females that laid eggs during observations, females with hernias laid significantly fewer eggs (35.8 ± 4.2) than intact females (48.0 ± 2.7) during the 4-hr interval. There was no difference in the mean proportion of hatch for eggs collected from the same n = 10 females before (0.88 ± 0.03) or after decapitation (0.84 ± 0.04). Rapid oviposition following decapitation suggests that WCR egg laying is under constant descending neural inhibition; the motor programme controlling egg laying must reside posterior to the head. Decapitation can be used to quickly collect mature, fertilized WCR eggs.     

Electrophysiological and behavioural response of Aedes albopictus to n‐heinecosane,an ovipositional pheromone of Aedes aegypti

Aedes aegypti (L.) and Aedes albopictus (Skuse) (Diptera: Culicidae) are highly anthropophilic mosquito species and potential vectors of dengue and yellow fever. The location of suitable sites for oviposition requires a set of visual, tactile, and olfactory cues that influence females before they lay their eggs. In this study, the effect of n‐heneicosane, a recognized oviposition pheromone of Ae. aegypti, on the olfactory receptors of the antennae of Ae. aegypti and Ae. albopictus was studied using electroantennographic detection coupled to gas chromatography (GC‐EAD). A significant electroantennographic response to n‐heneicosane in adult females of both mosquito species was observed. In addition, gravid Ae. albopictus females laid more eggs in substrate treated with n‐heneicosane at 0.1, 1, or 10 p.p.m. than in the control, denoting oviposition attractancy. Conversely, at 30, 50, 100, and 200 p.p.m., more eggs were laid in the control substrate, indicating oviposition repellency. Analysis of the larval cuticle by GC and mass spectrometry confirmed the presence of n‐heneicosane in the cuticles of Ae. albopictus larvae. The species‐specific role of n‐heneicosane as an oviposition pheromone in Ae. aegypti and its significance as a behaviour modifier of Ae. albopictus in breeding sites is discussed.     

Potential Costs of Selecting Good Sites For Offspring: Increased Risk of Drowning And Negative Effects on Egg Production

Many studies have shown the benefits of selecting suitable sites for offspring survival and growth. However, costs of selecting suitable sites have been little covered. If the female's costs associated with selecting suitable sites exceed the benefit from improvement of offspring performance, selecting such sites can have a negative effect on the ongoing reproductive success for ovipositing females. We investigate the potential costs of selecting suitable sites in the water strider Aquarius paludum insularis. Where there exists a risk of egg parasitism, the female A. paludum will submerge and select a deep site, more suitable for offspring survival, for oviposition. By forcing A. paludum underwater once a day for 10 d, we investigated the potential costs associated with oviposition at deep sites, firstly relating to the performance of submergence (latency to asphyxiation or proportion of buoyancy loss) and, secondly, in the number of eggs laid. Buoyancy became weaker and the latency to asphyxiation became shorter with the number of submergences. The number of eggs laid in the period of forced submergence was smaller than both before and after the period. Selecting deep sites can therefore increase the mortality risk of ovipositing females and also decrease the number of eggs laid in their lives. Selecting suitable sites in all the oviposition bouts can decrease ovipositing females' reproductive success. Costs, not only benefits, should be taken into consideration for understanding oviposition site selection during the lifespan of an ovipositing female.     

Functional response and egg distribution among hosts by Pseudapanteles dignus,a larval endoparasitoid of Tuta absoluta

The functional response of a biocontrol agent has been classically pointed out as a quantitative evaluation criterion to understand its killing capacity to an arthropod pest. In this paper, we revisited the functional response of the internal larval parasitoid Pseudapanteles dignus (Muesebeck) (Hymenoptera: Braconidae), a candidate for biocontrol of the South American tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), measured as the daily egg oviposition of single parasitoid females at increasing densities of T. absoluta larvae through dissection of hosts. The functional response curve of the number of parasitized hosts was fitted out taking into account the number of eggs laid and their distribution among hosts at each T. absoluta larval density. The data also allowed us to discuss the self-superparasitism strategy of this parasitoid as an adaptive trait. Pseudapanteles dignus showed a sigmoid shape functional response and a contagious distribution of eggs among hosts, favouring self-superparasitism and laying a similar number of eggs in each superparasitized host at each T. absoluta density. This research is firstly intended to ascertain about the oviposition behaviour of P. dignus and additionally to provide information on its reproduction to be applied in mass rearing procedures and augmentative releases against T. absoluta.     

Within‐patch oviposition site shifts by spider mites in response to prior predation risks decrease predator patch exploitation

In egg‐laying animals with no post‐oviposition parental care, between‐ or within‐patch oviposition site selection can determine offspring survival. However, despite the accumulation of evidence supporting the substantial impact predators have on oviposition site selection, few studies have examined whether oviposition site shift within patches (“micro‐oviposition shift”) reduces predation risk to offspring. The benefits of prey micro‐oviposition shift are underestimated in environments where predators cannot disperse from prey patches. In this study, we examined micro‐oviposition shift by the herbivorous mite Tetranychus kanzawai in response to the predatory mite, Neoseiulus womersleyi, by testing its effects on predator patch exploitation in situations where predatory mites were free to disperse from prey patches. Adult T. kanzawai females construct three‐dimensional webs on leaf surfaces and usually lay eggs under the webs; however, females that have experienced predation risks, shift oviposition sites onto the webs even in the absence of current predation risks. We compared the predation of eggs on webs deposited by predator‐experienced females with those on leaf surfaces. Predatory mites left prey patches with more eggs unpredated when higher proportions of prey eggs were located on webs, and egg survival on webs was much higher than that on leaf surfaces. These results indicate that a micro‐oviposition shift by predator‐experienced T. kanzawai protects offspring from predation, suggesting adaptive learning and subsociality in this species. Conversely, fecundity and longevity of predator‐experienced T. kanzawai females were not reduced compared to those of predator‐naïve females; we could not detect any costs associated with the learned micro‐oviposition shift. Moreover, the previously experienced predation risks did not promote between‐patch dispersal of T. kanzawai females against subsequently encountered predators. Based on these results, the relationships of between‐patch oviposition site selection and micro‐oviposition shift are discussed.     

Seasonal and cultivar-associated variation in oviposition preference of Oriental fruit moth (Lepidoptera: Tortricidae) adults and feeding behavior of neonate larvae in apples

The Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) has become a pest of tree fruits since its introduction to the United States in the early twentieth century. Oriental fruit moth has historically been a major pest problem in peach production, and outbreaks in commercial apple (Malus spp.) orchards in the eastern United States were rare until the late 1990s. Recent outbreaks in Mid-Atlantic apple orchards have lead researchers to investigate host-associated effects on oriental fruit moth biology, behavior, and population dynamics. Studies were designed to assess cultivar level effects in apples on oviposition and larval feeding behavior of oriental fruit moth. In a mixed cultivar apple orchard, total oriental fruit moth oviposition and oviposition site preferences varied between cultivars. These preferences also varied over time, when sampling was repeated at various times of the growing season. Although most adult female oriental fruit moth preferentially oviposited in the calyx and stem areas of apple fruit, noticeable numbers of eggs also were laid on the sides of fruit, contradicting some previous reports. Oriental fruit moth females exhibited a strong ovipositional preference for fruit that were previously damaged by oriental fruit moth or codling moth, Cydia ponmonella (L.). The majority of newly hatched oriental fruit moth larvae were observed to spend <24 h on the surface of apple fruit before entry, and this behavior was observed on several apple cultivars. Neonate larvae exhibited a preference for entering fruit at either the stem or calyx ends, regardless of their initial site of placement. Our findings underscore the importance of adequate spray coverage and accurate timing of insecticide applications targeting oriental fruit moth.     

Susceptibility of selected apple cultivars to the Mediterranean fruit fly

Ceratitis capitata (Wiedemann), the Mediterranean fruit fly, is one of the key pest species affecting deciduous fruit orchards along the Mediterranean coasts. Because of global warming, C. capitata is gradually spreading north and is becoming a major pest of apples. Determining the susceptibility of the main apple varieties grown in the region will serve as a cornerstone to the management of this pest. In this study, we show the results of a field and laboratory no‐choice test conducted to determine the Medfly preferences on different apple cultivars. The seven main varieties of apples (Gala, Red Delicious, Golden Delicious, Granny Smith, Kanzi, Morgen Dallago and Fuji) were tested. The results demonstrate that C. capitata lays eggs on all apple cultivars in both field and laboratory conditions. The Granny Smith, Red Delicious and Morgen Dallago varieties showed the lowest susceptibility in laboratory conditions, (0.75, 1.55, 2 oviposition punctures/fruit, respectively), with significant differences in oviposition compared to the Golden Delicious, Kanzi and Fuji (3.27, 3.31, 3.1 oviposition punctures/fruit, respectively) varieties, which were shown to be the most susceptible to Medfly attack in laboratory conditions. On the other hand, only slight and not statistically significant differences emerged from the field trials. In relation to the physico‐chemical characteristics, the apple cultivars showing the lowest susceptibility (Granny Smith, Red Delicious and Morgen Dallago) had harder peels and pulps and lower sugar contents than the most susceptible cultivars (Golden Delicious, Fuji and Kanzi). These results were also confirmed through evaluation of larval development on different varieties. In fact, Granny Smith, Red Delicious and Morgen Dallago were the three varieties that did not allow adequate larval and adult development and reduced the possibility of the emergence of a new generation.     

Effects of immune challenge on the oviposition strategy of a noctuid moth

Infections can have detrimental effects on the fitness of an animal. Reproducing females may therefore be sensitive to cues of infection and be able to adaptively change their oviposition strategy in the face of infection. As one possibility, females could make a terminal investment and shift reproductive effort from future to current reproduction as life expectancy decreases. We hypothesized that females of the noctuid moth Heliothis virescens make a terminal investment and adapt their oviposition timing as well as their oviposition site selectivity in response to an immune challenge. We indeed found that females that were challenged with the bacterial entomopathogen Serratia entomophila laid more eggs than control females one night after the challenge. Additionally, bacteria‐challenged females were less discriminating between oviposition sites than control females. Whereas control females preferred undamaged over damaged plants, immune‐challenged females did not differentiate between the two. These results indicate that terminal investment is part of the life history of H. virescens females. Moreover, our results suggest that the strategy of terminal investment in H. virescens oviposition represents a fitness trade‐off for females: in the face of infection, an increase in oviposition rate enhances female fitness, whereas low oviposition site selectivity reduces female fitness.     

Is the predatory mite <Emphasis Type="Italic">Kampimodromus aberrans</Emphasis> a candidate for the control of phytophagous mites in European apple orchards?

The most important biocontrol agents of phytophagous mites (mainly Tetranychidae) in European apple orchards are the predatory mites Amblyseius andersoni, Typhlodromus pyri and Euseius finlandicus (Phytoseiidae). A similar situation is found in Trentino (north-eastern Italy), an important apple production area in Europe. Another phytoseiid mite, Kampimodromus aberrans, can be dominant in neglected fruit orchards but is rare in commercial orchards because of its susceptibility to pesticides. However, pesticide resistant strains of K. aberrans have recently been found in vineyards. In the late 1990s, one of these resistant strains was successfully released on an experimental farm in Trentino. Kampimodromus aberrans spread to an apple orchard, despite the fact that it was colonized by T. pyri, A. andersoni and E. finlandicus, and became the dominant species. Since K. aberrans’ colonization appeared to be affected by apple cultivars, experiments were conducted on potted plants of three selected apple cultivars (Golden Delicious, Red Chief, Reinette du Canada). The results stressed the effect of cultivars on apple colonization by K. aberrans and suggested the role of leaf morphology in influencing this phenomenon. Field releases of K. aberrans were successfully performed in four commercial apple orchards. The incidence of K. aberrans in the total phytoseiid population increased over time and the predator became dominant in the season following its release in two orchards. Kampimodromus aberrans persists in these orchards as the dominant species. The adaptation of K. aberrans to varying environmental conditions, its tolerance to pesticides, and its competitiveness towards other phytoseiid species suggest a potential role of this species in the biological control of phytophagous mites in European apple orchards. Handling editor: Eric Lucas.     

Behavioral analysis of learning and memory in Anastrepha fraterculus

We evaluate the influence of prior exposure to artificial substrate for oviposition on learning and memory in the fruit fly Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae). Some females were previously exposed to artificial fruits made of water, agar, and blackberry [Rubus spec. (Rosaceae)] or guava [Psidium guajava L. (Myrtaceae)] pulp for 48 and 72 h. We also studied adult flies exposed for 72 h to essential oil of lemongrass [Cymbopogon citratus (DC) Stapf, Poaceae] and adult flies from larvae exposed to the oil. Control females were naive with respect to these experimental substrates. Prior experience with blackberry‐based artificial fruits resulted in an increase in the number of punctures and deposited eggs by A. fraterculus, and memory lasted for up to 72 h. On the other hand, fly behavior was independent of exposure to guava‐based substrate. Prior exposure of 1‐ or 15‐day‐old females to artificial substrate with lemongrass oil modified innate substrate selection behavior. The scent of lemongrass oil during the larval stage modified innate oviposition responses of adult A. fraterculus. The study shows that A. fraterculus females are able to learn and retain information through chemical stimuli released by both host (blackberry and guava) and non‐host (lemongrass) species, and they can use olfactory memory obtained during the larval stage to select oviposition sites.     

Effect of adult females' predation risk on oviposition site selection in a water strider

In many egg‐laying species, females avoid ovipositing at sites where the predation risk is high. Previous studies have mainly focused on the risk for offspring. The effect of predation risk for the females has been considered in some taxa in which parents spend much time at an oviposition site for parental care or mating (e.g., birds, amphibians). In species in which females do not perform activities other than oviposition at sites, the effect of predation risk for females on oviposition site selection has been rarely investigated. We examined whether the predation risk for ovipositing females affects the decision on oviposition in the water strider Aquarius paludum insularis (Motschulsky) (Heteroptera: Gerridae). Adult A. paludum are preyed upon by a backswimmer, Notonecta triguttata (Motschulsky) (Heteroptera: Notonectidae), but N. triguttata does not prey upon eggs or early instars of A. paludum. We allowed female A. paludum to oviposit under one of three conditions: in presence of N. triguttata, in presence of its chemicals, and in absence of the predator or its cues (control). Female A. paludum less frequently oviposited in presence of N. triguttata than in its absence. Oviposition frequency did not differ between females in presence of chemicals of N. triguttata vs. those in the control. Female A. paludum recognized the predation risk upon themselves from the presence of N. triguttata and avoided ovipositing. This study is the first to directly show that the predation risk upon ovipositing females changes oviposition site selection in species in which the time spent at an oviposition site is short.     

Development and biological characteristics of <Emphasis Type="Italic">Haemaphysalis longicornis</Emphasis> (Acari: Ixodidae) under field conditions

The development and biological characteristics of Haemaphysalis longicornis were investigated under field conditions in Xiaowutai National Natural Reserve Area, North China. Unfed larvae, nymphs and adults were fed on rabbits and exposed to daylight. Three free-living stages were allowed to develop in field plot selected in a tick natural habitat. The host seeking behavior and seasonal occurrence were observed. Haemaphysalis longicornis were active from mid March to mid October. The premoult period of nymphs and preoviposition of females were regulating phases of their life cycle. The developmental durations of eggs, larvae and adults were constant under field conditions regardless when the development started. The oviposition periods in May and June were statistically shorter than those in July and August. The daily oviposition patterns of females engorged in May and June demonstrated unobvious peak, which differed from those engorged in July and August. The daily oviposition peak of the latter occurred on the 4th day of oviposition. Moreover, a positive correlation was found between the mass of the laid egg and the body weight of engorged females (r = 0.62, P < 0.001). The female reproductive efficiency indices were 2.9, 6.1, 10.5 and 9.0 in May, June, July and August, respectively. The mean weight (3.33 mg) of engorged nymphs molting to females was significantly higher than that (2.35 mg) of those molting to males (P < 0.001), but the body weights of both sexes were overlapping.     

Diving Into The Water: Cues Related to the Decision‐Making by an Egg Parasitoid Attacking Underwater Hosts

Although adult parasitoids spend a majority of their lives above ground, females of several species must search for their host in the water or on the soil. Adult parasitoids above ground can use a variety of sensory cues to detect their hosts from a distance. However, their sensory cues can be impaired from volatile chemicals, and their visual stimuli can be decreased while submerging or burrowing in the water of soil during their search for their hosts. Searching underwater or underground would incur high foraging costs, that is, time and energy consumption and increase risk of drowning. Therefore, to reduce such costs and increase searching efficiency, the decision on where to start submerging or burrowing for attacking hosts is important for parasitoids. Furthermore, there are no studies that have examined the cues of submerging or burrowing parasitoids on their exploit for the decision to attack their hosts. We have examined the cues used by the egg parasitoid Tiphodytes gerriphagus attacking underwater hosts. We compared the searching behaviors of T. gerriphagus among four oviposition site conditions. The four sites investigated were oviposition site with both host adult chemical residues and presence of eggs, with only the presence of eggs, with only the host adult chemical residues, and without any cue. Our results indicated that T. gerriphagus more frequently contacted and submerged at oviposition sites with the adult residues rather than at oviposition sites without them. Nonetheless, the presence of underwater host eggs did not affect the host‐searching behavior. This suggests that T. gerriphagus decided to submerge at the oviposition site in response to the adult residues. Furthermore, our observation also suggested that T. gerriphagus has already detected that the adult residues might be volatile before contacting the oviposition site. Finally, we will discuss the exploitation patterns of host‐searching cue by parasitoids that need to submerge from the context of its reliability and detectability problems.     

Influence of protein hydrolysate baits on oviposition in the apple maggot, Rhagoletis pomonella

Ovipositional responses of apple maggot (AM), Rhagoletis pomonella (Walsh), females were studied in the laboratory on apples (var: Golden Delicious) treated with different rates of four protein hydrolysate baits in choice and no-choice tests. Protein hydrolysate baits at rates of 0.5 and 1% had no significant effect, but oviposition was greatly reduced at higher rates of 5 and 10%. Apple maggot females exposed to apples treated with protein hydrolysate baits at a rate of 10% made 41–71% fewer punctures and laid 41–73% fewer eggs than in untreated control. No oviposition activity was shown on apples treated with 25 and 100% Nulure®. In no-choice tests the AM females laid 75–96% fewer eggs in apples treated with 10 and 25% Nulure compared to controls and no oviposition occurred in apples treated with 100% Nulure. Apple maggot females arrived in similar numbers on apples treated with 10% Nulure and untreated apples, but only 5% of those arriving on Nulure-treated apples showed ovipositor boring with no egg deposition while 60% of females arriving on untreated apples showed ovipositor boring activity and laid an average of 2.5 eggs per apple. In another experiment, individual AM females displayed similar behavioral responses to 10% Nulure-treated apples; none of the 56 females tested on treated apples displayed ovipositor boring activity, but 59% of the females (N=56) tested on untreated apples displayed ovipositor boring within 5 min of their arrival. Ninetyeight percent of AM females stayed and fed on fruit surfaces for 5 min on Nulure-treated apples without ovipositor boring compared to only 2% on untreated apples. Of the females that arrived on untreated apples, 39% flew away within 5 min without ovipositor boring compared to only 2% of those that arrived on Nulure-treated apples. Results of these two behavioral experiments suggest that upon arrival on a protein bait-treated apple, an apparent change of behavior occurs in AM females and instead of attempting to oviposit, they attempt to feed on fruit surfaces resulting in reduced oviposition activity. These results indicate that the feeding and oviposition-related activities of AM females are probably mutually exclusive and that the feeding behavior preempts oviposition activities on host fruits treated with higher rates of protein hydrolysate baits.     

Seasonal monitoring of Drosophila suzukii and its non-crop hosts in Wuhu,Eastern China

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a serious pest that prefers fresh fruits and is native to Southeast Asia. In our study, apple cider vinegar bait traps were used to capture and monitor the population dynamics of this native pest in Wuhu City, China, from May/June 2017 to May 2018. The research was conducted at 15 locations in two fruit orchards in Wuhu. Traps caught more adults in general in a Meiling blueberry orchard than in a Xicun mixed orchard, and the highest trap counts occurred near harvest time (October). Females had more mature eggs from September to November, and the number of mature eggs declined thereafter. We found several non-crop hosts, which can provide food and reproductive resources for D. suzukii and are common in forests and field margins. By comparing the number of captured adults in the Meiling and Xicun orchards, we found that blueberry was preferred by D. suzukii among the fruits in our search. Fruit ripening times differed among crops; therefore, fly populations moved between crop and non-crop habitats during the year or had varying population dynamics on different crops in different seasons. The D. suzukii population and the number of mature eggs decreased in summer and winter but increased in spring and autumn. Drosophila suzukii had higher survival rates with blueberry than those with other fruits, and D. suzukii could use four non-crop species growing around the orchards as host plants.     

Influences of temperature and humidity on the life history parameters and prey consumption of <Emphasis Type="Italic">Anthocoris minki</Emphasis> Dohrn (Heteroptera: Anthocoridae)

Anthocoris minki Dohrn is a promising indigenous Anthocoris species for the biological control of Agonoscena pistaciae Burck. and Laut. (Homoptera: Psyllidae) in pistachio orchards in Turkey. The adult longevity, fecundity, life table parameters and prey consumption of A. minki fed on Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs were studied at combinations of three constant temperatures (20, 25 and 30 ± 1°C) with two relative humidity (RH) levels (40 and 65 ± 5%). Studies indicated that temperature and RH significantly affected adult longevity, fecundity and prey consumption of A. minki. The greatest adult female longevity was 116.0 days at 20°C and 65% RH; the shortest adult female longevity was 27.5 days at 30°C and 40% RH. At all tested temperatures, the oviposition period and prey consumption of both females and males significantly decreased at low RH compared to high RH. The highest and lowest total fecundities were 276.0 eggs (at 20°C and 65% RH) and 42.4 eggs (at 25°C and 40% RH), respectively. The intrinsic rates of natural increase (r _m) at 40 and 65% RH were 0.049 and 0.076 at 20°C, 0.072 and 0.096 at 25°C and 0.076 and 0.112 at 30°C, respectively. The highest mean numbers of E. kuehniella eggs consumed by females and males were 859.6 (at 20°C) and 515.3 (at 25°C) at 65% RH, respectively; the lowest were 183.3 (at 20°C) and 95.5 (at 25°C) at 40% RH, respectively.