Mate recognition inCryptomyzus aphids: copulation and insemination

The acceptability of three widely distributed Australian Menispermaceae,Tinospora smilacina Benth.,Sarcopetalum harveyanum F. Muell. andStephania japonica (Thunb.) Miers, as food for larvae of the fruitpiercing moth,Othreis fullonia (Clerck), was examined in three laboratory experiments. When larvae were presented with plant species individually total development times were shortest onT. smilacina and longest onS. japonica, despite relatively similar consumption rates within most instars.T. smilacina elicited greater (P<0.05) relative growth rates thanS. japonica in all instars except the 6th. In the second experiment, when larvae were allowed to select from each of the 3 plants, noS. japonica was chosen by 1 st instars and it represented only 3.7% of food consumed by 2nd instars. Significantly moreT. smilacina was eaten in each instar thanS. japonica, and more thanS. harveyanum except in the 2nd and 4th instars. The final experiment examined the abilities of larvae to switch hosts when forced after the 1st and 3rd instars. After the first or second food change largest average headcapsule widths were associated with feeding onT. smilacina as the most recent food. Feeding by final instars onT. smilacina also resulted in the shortest development time and highest puparial weights. While some larvae survived irrespective of plant sequence 83.3% of the recorded mortality occurred while larvae were exposed toS. japonica, principally during the 1st instar. These experiments lend support to field observations which suggest thatT. smilacina is a major host ofO. fullonia whileS. japonica is notS. harveyanum is probably an important alternate host whenT. smilacina is scarce.     

Effectiveness of Heterohabditis bacteriophora strain GPS11 applications targeted against different instars of the Japanese beetle Popillia japonica

Field and laboratory tests were conducted from 2001 through 2007 to assess the effectiveness of entomopathogenic nematode Heterorhabditis bacteriophora strain GPS11 applications targeted against different instars of the Japanese beetle, Popillia japonica. During summer flight, P. japonica adults were trapped and caged on turfgrass plots for oviposition. Larval development was monitored for the occurrence of each instar. Nematodes were applied in the field against each developing instar at 2.5 × 10⁹ infective juveniles/ha. In 2001, field data obtained in October resulted in 75%, 53%, and 33% control with the applications targeted against the first, second, and third instars, 69, 28, and 9 days after treatment (DAT), respectively. In 2002 field trial, data obtained in October indicated 97%, 88%, and 0% control when the applications were targeted against the first, second, and third instars at 66, 43, and 14 DAT, respectively. Additional plots established in 2002 to determine efficacy against each instar at 14 DAT showed control of the first, second, and third instars to be 55%, 53%, and 0%, respectively. In laboratory tests conducted in 2002, 2004, and 2007, P. japonica collected from the field at the occurrence of each instar were exposed to H. bacteriophora at concentrations of 0, 10, 33, 100, 330, or 1000 infective juveniles/grub. Probit analysis of the mortality from three of the four sets of tests conducted showed the first instar to be significantly more susceptible to H. bacteriophora than the third instar at the LC₅₀ level and all tests showed the first instar to be significantly more susceptible than the third instar at the LC₉₀ level. In addition to the observed decrease in the third instar susceptibility to H. bacteriophora, soil temperatures in the mid-western United States during late September and October rapidly decline often reaching below 15 °C by the beginning of October when grubs are in the third instar stage of development. Therefore, we conclude that the applications of the nematodes made in August or September will provide higher control than those made in October, due to the more appropriate temperature for nematode activity and the presence of more susceptible larval stages. Early nematode applications may also provide an opportunity for nematodes to recycle and cause secondary infections.     

Endophyte infection in perennial ryegrass reduces the susceptibility of black cutworm to an entomopathogenic nematode

Abstract The perennial ryegrass, Lolium perenne, forms a symbiotic relationship with Neotyphodium lolii, a fungus that produces alkaloids. This relationship provides a competitive advantage to the host plant in grassland communities by increasing drought tolerance, and disease and herbivore resistance. Black cutworm, Agrotis ipsilon, is among the few insect species that are able to feed and develop on endophytic perennial ryegrass. Some insects can use plant secondary compounds to defend themselves against predators, therefore we hypothesized that the cutworms fed on endophytic grasses would exhibit greater defense against a lethal endoparasitic nematode, Steinernema carpocapsae. Laboratory experiments involving 4–5th instars support the hypothesis that A. ipsilon feeding on grass clippings from field plots with high (> 90%) incidence of endophyte infected perennial ryegrass are less susceptible to entomopathogenic nematodes than larvae fed grass clippings from plants with little or no incidence of endophyte. Laboratory studies resulted in similar overall mortality after 48 h. Field studies, however, show decreased susceptibility to S. carpocapsae when larvae were confined to areas of endophytic grass (> 75% infected). Early instars (2–3rd) fed on endophyte free grass suffered greater overall mortality at all nematode concentrations than 4–5th instars fed similarly. Early (2–3rd) instars were equally susceptible to nematode attack regardless of food source. Our results indicate that the fungal endosymbionts of grasses can influence the biology of natural enemies of an herbivorous insect.     

Population dynamics ofLuehdorfia japonica Leech (Lepidoptera: Papilionidae)

Mortality processes from egg to final instar larval stage are examined in the papilionid butterfly Luehdorfia japonica for two generations in a natural populations. Special attention is given to the effects of initial egg cluster size on the survival rate by the 3rd instar. Mean egg cluster sizes for the two generations were 11.3 and 10.7. The hatching rate was not affected by the egg cluster size. Up to 3rd instar, larvae in a group were more likely to die en masse rather than to die individually, whereas most larvae in later instars died independently. The egg clusters of the average (and the most frequent) size class (11±1) had the second highest survival rate until the 3rd instar. A slightly higher survival rate occurred in clusters a little larger (14±1). The average size clusters were least likely to be exterminated and about 70% of them produced at least one individual surviving to the 3rd instar. Factors affecting the observed mortality patterns were discussed.     

Biological control of Tipula paludosa (Diptera: Nematocera) using entomopathogenic nematodes (Steinernema spp.) and Bacillus thuringiensis subsp. israelensis

Tipula paludosa (Diptera: Nematocera) is the major insect pest in grassland in Northwest Europe and has been accidentally introduced to North America. Oviposition occurs during late August and first instars hatch from September until mid-October. Laboratory and field trials were conducted to assess the control potential of entomopathogenic nematodes (EPN) (Steinernema carpocapsae and S. feltiae) and Bacillus thuringiensis subsp. israelensis (Bti) against T. paludosa and to investigate whether synergistic effects can be exploited by simultaneous application of nematodes and Bti. Results indicate that the early instars of the insect are most susceptible to nematodes and Bti. In the field the neonates prevail when temperatures tend to drop below 10 °C. S. carpocapsae, reaching >80% control, is more effective against young stages of T. paludosa than S. feltiae (<50%), but the potential of S. carpocapsae might be limited by temperatures below 12 °C. Mortality of T. paludosa caused by Bti was not affected by temperature even at 4 °C but the lethal time increased with decreasing temperatures. Synergistic effects of Bti and EPN against T. paludosa were observed in 3 out of 10 combinations in laboratory assays but not in a field trial. The potential of S. carpocapsae was demonstrated in field trials against early instars in October reaching an efficacy of >80% with 0.5 million nematodes m⁻² at soil temperatures ranging between 3 and 18 °C. Results with Bti were strongly influenced by the larval stage and concentration. Against early instars in autumn between 74 and 83% control was achieved with 13 kg ha⁻¹ Bti of 5,700 International Toxic Units (ITUs) and 20 kg ha⁻¹ of 3,000 ITUs. Applications in spring against third and fourth instars achieved between 0 and 32% reduction. The results indicate that application of Bti and nematodes will only be successful and economically feasible during the early instars and that the success of S. carpocapsae is dependent on temperatures >12 °C. Synergistic effects between S. carpocapsae and Bti require more detailed investigations in the field to determine maximal effect.     

Comparative population ecology of Ephydra hians Say (Diptera: Ephydridae) at Mono Lake (California) and Abert Lake (Oregon)

The population dynamics of Ephydra hians Say final instar larvae and pupae were compared over a two year period in rocky littoral habitats of two alkaline saline lakes in the western Great Basin. Relative abundance increased from 1983 to 1984 at Mono Lake (California), during dilution from ca. 90 to 80 g 1^-1 TDS (total dissolved solids). In contrast, relative abundance decreased over the same period at Abert Lake (Oregon), accompanied by a dilution of salinity from ca. 30 to 20 g l^-1 and a marked increase in the number and abundance of other benthic macroinvertebrate species. These observations are consistent with a hypothesis that proposes biotic interactions limit E. hians abundance at low salinity, and physiological stress limits abundance at high salinity.Oviposition extends from early spring to early fall. Mixed instars present throughout this period indicates multivoltine population dynamics with overlapping generations. The standing stock biomass of final instars increases exponentially in late spring and peaks in late summer or early fall. Pupae increase in proportional representation and abundance from a spring minimum to a fall maximum. The body size of adults and pupae cycle seasonally from a spring maximum to a fall minimum, and may be related to either or both food limitation, or water temperature.     

Occurrence of Alternaria japonica on Seeds of Wild and Cultivated Rocket

In vitro evaluation was carried out on seed samples of wild and cultivated rocket cultivars, most frequently grown in Italy, and obtained from farms affected by the leaf spot caused by Alternaria japonica in Piedmont and Lombardy during the fall of 2010. Twelve seed samples were collected and assayed for the presence of A. japonica. The pathogen was isolated only from not disinfected seeds. Among the two seed samples of cultivated rocket (Eruca vesicaria), only one was infected by A. japonica at a level of one infected seed out of 800. Four out of ten samples of wild (Diplotaxis tenuifolia) rocket seeds were contaminated by A. japonica with the highest level of infection detected in a single sample of 3 out of 800. All tested isolates of A. japonica obtained from seeds were pathogenic on both wild and cultivated rocket.     

Synergism of Entomopathogenic Nematodes and Imidacloprid against White Grubs: Greenhouse and Field Evaluation

In previous greenhouse studies, the insecticide imidacloprid and the entomopathogenic nematode Heterorhabditis bacteriophora Poinar interacted synergistically against third instars of the masked chafers Cyclocephala hirta LeConte and C. pasadenae Casey (Coleoptera: Scarabaeidae). We tested this interaction for two additional nematode species and three additional scarab species under field conditions. In greenhouse tests, H. bacteriophora and Steinernema glaseri (Steiner) interacted synergistically against third instars of the Japanese beetle, Popillia japonica Newman, the oriental beetle, Exomala orientalis Waterhouse, and the masked chafers Cyclocephala borealis Arrow, C. pasadenae, and C. hirta. The degree of interaction varied with nematode species. The strongest synergism occurred between imidacloprid and S. glaseri. Synergism between imidacloprid and H. bacteriophora was weaker and the interaction was not always significant. Combinations of imidacloprid and S. kushidai Mamiya only resulted in additive mortality. The synergistic interaction was also observed in field trials but the results were more variable than those under greenhouse conditions. The combination of nematodes and imidacloprid could be used for curative treatments of white grub infestations, especially against scarab species that are less susceptible to nematodes and/or imidacloprid. This combination has a low environmental impact and high compatibility with natural biological control of turfgrass insects. The possible roles of these combinations in augmentative control approaches are discussed.     

Stage-dependent feeding behavior by western tarnished plant bugs influences flower bud abscission in cotton

Unexplained variability in the relationship between the number of herbivores in a field and the amount of crop damage can arise if there is a large amount of variation among herbivore individuals in the amount of feeding damage each generates. In California, populations of the western tarnished plant bug, Lygus hesperus Knight (Heteroptera: Miridae), produce highly variable levels of damage to cotton plants (Gossypium hirsutum L.) (Malvaceae), even when found at low densities. Because L. hesperus populations are also highly variable in their overall stage structure, we hypothesize that differences in crop damage might result from varying impact by each L. hesperus stage on cotton flower buds (termed squares). Laboratory measurements of L. hesperus mouth‐parts and distance to anther sacs, a preferred feeding site, revealed that 1st?3rd instar L. hesperus nymphs will not be able to feed on anther sacs of larger squares (over 8 mm in length) but will be able to feed on squares that are most sensitive to L. hesperus damage (<7 mm). Because even the 1st instars can feed on the most sensitive ‘pinhead’ squares, size constraints do not rule out damaging effects from the youngest L. hesperus. Laboratory observations revealed that later developmental stages, and adults, spend more time feeding on cotton squares relative to 2nd and 3rd instars. In addition, a field experiment revealed no effect of 2nd instars on square retention (relative to control cages) but did reveal a significant decrease in square retention generated by adult L. hesperus (4th instar L. hesperus resulted in an intermediate level of square retention). In a final study we sampled L. hesperus stage structure and density across 38 cotton fields. Multiple regression revealed that the densities of 1st?3rd instars of L. hesperus are not correlated with anther sac damage or square retention. However, in 2 years 4th and 5th instars were positively correlated with anther sac damage and negatively correlated with square retention. In the a third year, adult L. hesperus showed correlations in the same direction, across fields and across sites within fields. Overall, these results suggest that the adults and the largest nymphs of L. hesperus (4th and 5th instars) are particularly damaging to cotton squares, with the 1st?3rd instars of L. hesperus causing little damage to plants.     

The ontogeny of Loxoconcha japonica Ishizaki, 1968 (Cytheroidea, Ostracoda, Crustacea)

The ontogeny of the cytheroidean species Loxoconcha japonica is documented from the earliest instar to the adult. The first instar (instar A-8) of L. japonica is different from that of cypridoidean species in that it has an additional appendage, the furca, present. From instar A-7 onwards, the appearance of the appendages is similar to that of cypridoidean and bairdioidean species. The furca is well developed in instars A-8 to A-5, and is probably an important appendage in these early instars, despite its reduced form in the adults. Some appendages of L. japonica (e.g. the antennae) gain very few setae and claws through ontogeny, compared with species from other superfamilies. This possibly reflects paedomorphic evolution of this species.     

Host plant, oviposition behavior and larval ecology of a sawfly leafminer, Profenusa japonica (Hymenoptera: Tenthredinidae)

The host plant, oviposition behavior and larval ecology of Profenusa japonica Togashi are reported for the first time. Adults of P. japonica mated and oviposited on a polyantha rose, Rosa multiflora (Rosaceae), in April. Each female adult laid an egg on the edge of a leaflet. Hatched larvae consumed the parenchymatous layer of leaflets and in so doing created a mine. The larval stage comprised five instars. On average, 70.6% of the total area of a leaflet was consumed by one larva. Female adults of P. japonica laid eggs singly, probably to avoid larval competition for food.     

Host suitability of different instars of the whitefly Bemisia tabaci `biotype Q' for Eretmocerus mundus

Eretmocerus mundus Mercet is a parasitoidof Bemisia tabaci (Genn.) indigenous tothe Mediterranean and is used commercially foraugmentative biological control in Spain andelsewhere. A better understanding of thesuitability of different host instars wouldhelp optimize production and field application.Incidence of parasitism, development time,survivorship and sex ratio were evaluated whendifferent nymphal instars of the sweetpotatowhitefly Bemisia tabaci biotype `Q' wereoffered for parasitization. Experiments wereconducted on sweet pepper at 25 °C, 75%RH and 16:8 (L:D) photoperiod. E. mundusoviposited in all nymphal instars of B.tabaci except the mature 4th instar orpharate adult (previously designated, `pupa').Incidence of parasitism was greatest (33.8± 5.1 parasitized nymphs) and developmenttime shortest (14.1 ± 0.1 d) whenoviposition occurred under 2nd and3rd instar nymphs compared to 1st or4th instars. Survivorship (85%) andoffspring sex ratio (39.8% female) did notdiffer statistically for parasitoids developingin whiteflies that were parasitized asdifferent instars. Although 2nd and3rd instars were clearly the mostfavorable host stage for E. mundus, itscapacity to parasitize and develop on a widerange of host stages is a favorablecharacteristic for both rearing and fieldapplication.     

Virulence of the entomopathogenic nematodes Heterorhabditis bacteriophora, Heterorhabditis zealandica, and Steinernema scarabaei against five white grub species (Coleoptera: Scarabaeidae) of economic importance in turfgrass in North America

We compared the virulence of the entomopathogenic nematodes Steinernema scarabaei, Heterorhabditis zealandica, and Heterorhabditis bacteriophora (GPS11 and TF strains) against third instars of the Japanese beetle, Popillia japonica, the oriental beetle, Anomala (=Exomala) orientalis, the northern masked chafer, Cyclocephala borealis, the European chafer, Rhizotrogus majalis, and the Asiatic garden beetle, Maladera castanea, in laboratory and greenhouse experiments. The virulence of the nematode species relative to each other differed greatly among white grub species. H. bacteriophora and H. zealandica had similar modest virulence to P. japonica, A. orientalis, C. borealis, and M. castanea. But against R. majalis, H. zealandica showed low virulence with a clear concentration response whereas H. bacteriophora caused only erratic and very low mortality. In contrast, S. scarabaei had modest virulence against C. borealis, but was highly virulent against R. majalis, P. japonica, A. orientalis, and M. castanea with R. majalis being the most susceptible and M. castanea the least susceptible.     

Life cycle and abundance oflongitarsus jacobaeae [Col.: Chrysomelidae], biocontrol agent ofSenecio jacobaea

The life cycle and abundance of the tansy ragwort flea beetle,Longitarsus jacobaeae (Waterhouse), were investigated in a dune area in the Netherlands. The beetle overwinters in the egg stage, which is parasitised by a Mymarid wasp. No larvae were found until spring. Three larval instars can be separated by head capsule size and coloration. Initial larval numbers are high (up to 214 larvae per plant), but drop to very low levels by late spring. Adults appear during June or July, the numbers are high until October, the adults can be found until the end of December. This life cycle differs remarkably from those described for the species in Switzerland, Italy and Britain. Possible causes for these differences are discussed, as well as implications for the use ofLongitarsus in biological control.      

The toxicity of cadmium to different larval instars of the trichopteran larvae Agapetus fuscipes Curtis and the importance of life cycle information to the design of toxicity tests

The acute toxicity of cadmium to three larval instars (1 st, 3rd and 4th) of the cased trichopteran Agapetus fuscipes Curtis was determined for animals both in the cased and uncased state. First instar larvae were significantly more sensitive than 3rd or 4th instars and for all ages cased animals were more resistant than uncased. Sub-lethal toxicity was demonstrated by a reduction in case building activity and aggregation response. The need to consider life cycle information when designing toxicity testy and the importance of incorporating sub-lethal responses into a study are discussed.     

Descriptions of two new and one little known species of the genus Cacopsylla (Hemiptera: Psyllidae) on Sorbus japonica (Rosaceae) and an observation of their biology

Three species of the genus Cacopsylla were collected from Sorbus japonica in Japan. Two of them, Cacopsylla elegans and Cacopsylla sorbicoccinea, are described as new species based on adults and fifth (final) nymphal instars. The third species, Cacopsylla midoriae, is newly transferred from the genus Psylla. The adult of C. midoriae is redescribed and the nymph is described for the first time. A key to the species feeding on S. japonica (adults and nymphs) is provided. The three species were observed to coexist on the same tree of S. japonica in northern Kyushu. Such coexistence of psylloid congeners is uncommon in Japan.     

Infection and mortality of Microtheca ochroloma (Coleoptera: Chrysomelidae) by Isaria fumosorosea (Hypocreales: Cordycipitaceae) under laboratory conditions

Microtheca ochroloma Stål, the yellowmargined leaf beetle, is a pest in crucifer crops during the late fall and winter months in Florida. On organic farms, it is difficult to control due to the restricted use of insecticides, in addition to the lack of specific natural enemies. The objective of this study was to evaluate a blastospore-formulated product of Isaria fumosorosea (PFR-97^TM 20% WDG) against this beetle. In the first experiment, four of the beetle's life stages were treated with a suspension of 3 × 10⁷ blastospores/ml. Mean corrected mortality of treated insects was significantly higher in 1st and 3rd instars than in the egg, pupal, and adult stages. Larvae infected by I. fumosorosea exhibited reduced growth and unsuccessful molting. The second experiment quantified mortality of first instars of M. ochroloma by four concentrations of PFR-97^TM. Mean corrected larval infection/treatment was significantly (2.6 times) higher with a concentration of 4?g of product per 100?ml of water compared to concentrations of 1–3?g per 100?ml of water. Different factors that might have affected the pathogenicity of I. fumosorosea against M. ochroloma are discussed.     

Comparative susceptibility of larval instars and pupae of the western corn rootworm to infection by three entomopathogenic nematodes

As a first step towards the development of an ecologically rational control strategy against western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) in Europe, we compared the susceptibility of the soil living larvae and pupae of this maize pest to infection by three entomopathogenic nematode (EPN) species. In laboratory assays using sand-filled trays, Heterorhabditis bacteriophora Poinar and H. megidis Poinar, Jackson & Klein (both Rhabditida: Heterorhabditidae) caused comparable mortality among all three larval instars and pupae of D. v. virgifera. In soil-filled trays, H. bacteriophora was slightly more effective against third larval instars and pupae, and H. megidis against third larval instars, compared to other developmental stages. In both sand and soil, Steinernema feltiae (Filipjev) (Rh.: Steinernematidae) was least effective against second instars. In conclusion, all larval instars of D. v. virgifera show susceptibility to infection by all three nematodes tested. It is predicted that early application against young larval instars would be most effective at preventing root feeding damage by D. v. virgifera. Applications of nematodes just before or during the time period when third instars are predominant in the field are likely to increase control efficacy. According to our laboratory assays, H. bacteriophora and H. megidis appear to be the most promising candidates for testing in the field. I. Hiltpold similarly contributed to this paper as the first author.     

Synergies between biological and neonicotinoid insecticides for the curative control of the white grubs Amphimallon majale and Popillia japonica

Synergistic combinations of biological and chemical insecticides might yield promising alternatives for soil insect pest management. In turfgrass of the Northeast U.S., control of root-feeding scarab larvae is highly dependent on conventional insecticides. Studies on interactions between entomopathogenic nematodes and neonicotinoid insecticides, however, demonstrate the feasibility of synergies as an approach for reduced-risk curative control. To understand the breadth of potential synergies, we screened numerous combinations of biological control agents with sublethal doses of neonicotinoids against third instars. Interactions were characterized as synergistic, additive or antagonistic. The most promising combinations identified in laboratory bioassays were advanced to greenhouse pot studies and then to field trials featuring microplots with artificially infested populations. To reveal variation across scarab species, trials were conducted on Amphimallon majale and Popillia japonica. Synergies were consistent across trials and specific to white grub species. For A. majale, synergistic combinations of Heterorhabditis bacteriophora with imidacloprid and clothianidin were discernible in laboratory, greenhouse and field trials. For P. japonica, synergistic combinations of Beauveria bassiana and Metarhizium anisopliae with both neonicotinoids were discernible in the laboratory and greenhouse, but not in the field. For both species, antagonistic interactions were discernible between Bt-products and both neonicotinoids. While nematode-neonicotinoid synergies among scarab larvae have been examined before, fungi-neonicotinoid synergies are unreported. In the context of previous studies, however, no patterns emerge to explain variation across target species or control agent. Further study of non-additive interactions will guide how biological and chemical products could be combined to enhance soil insect pest management.     

Cotesia plutellae parasitizing Plutella xylostella: Host-age dependent parasitism and its effect on host development and food consumption

The braconid Cotesia plutellae(Kurdjumov) (Hymenoptera: Braconidae) is amajor solitary, larval endoparasitoid of thediamondback moth, Plutella xylostella(L.) (Lepidoptera: Plutellidae). Parasitism oflarvae of different host instars and fourdevelopmental ages of the 4th instar ofthe pest was examined. The effects of hostinstar at initial parasitization on thedevelopment, survival, size and fecundity ofthe parasitoid were determined in thelaboratory at 25 °C. The effects ofparasitism on host development and foodconsumption were investigated at 28 °C.Cotesia plutellae could parasitize larvaeof all four instars of P. xylostella, butpreferred 2nd and 3rd instars. In achoice test, the relative parasitism indicesfor 2nd, 3rd and 4th instarswere 0.37, 0.39 and 0.24, respectively.Parasitism decreased sharply with increasinghost age in the 4th instar and approachedzero in host larvae that had gone beyond 37%of 4th stadium. The development time andthe final adult size of the parasitoid variedwith the host instar at initial parasitization.Parasitoids with initial parasitism in the4th instar hosts had the shortestdevelopment time, followed by those in the3rd instar, and then by those in the2nd instar. Parasitoids startingparasitism in 2nd instar hosts weresmaller in body size than those starting in the3rd or 4th instar. However, resultantfemales starting parasitism in 3rd instarhosts had the highest fecundity. Parasitizedlarvae exhibited longer development time andincreased food consumption compared withunparasitized ones. This study presents thefirst record that a solitary parasitoidregulates host behavior leading to an increasein food consumption by the host.