Monitoring of rice weevil, Sitophilus oryzae, feeding behavior in maize seeds and the occurence of supernumerary molts in low humidity conditions

Rice weevils, Sitophilus oryzae (L.), complete their development from egg to early adulthood inside grains of wheat, rice or maize, but little is known about their feeding behavior within the seeds. An ultrasonic insect feeding monitor was used to characterize the feeding patterns of individual rice weevils as they developed in maize grains. Weevils reared in grains held at ca. 40% r.h. took longer to develop from egg to pupation than those reared in grains kept at ca. 70% r.h. Feeding patterns revealed that larvae developing in grains held at ca. 70% r.h. had only four instars, whereas supernumerary molts (five instars) occurred in certain individuals reared in grain held at ca. 40% r.h. The supernumerary molts may represent a response of the insect to stresses associated with low moisture levels in the seeds.     

Relationship between an increase of juvenile hormone titer in early instars and the induction of diapause in fully grown larvae of Sesamia nonagrioides

The larvae of Sesamia nonagrioides (Lepidoptera: Noctuidae) grown at 25 degrees C and long photoperiod (16:8h light:dark) pupate in the 5th or 6th (mostly) larval instar, while the larvae reared under a short photoperiod (12:12h) enter diapause during which they consume some food and undergo up to 12 (usually 3-4) stationary larval molts. Diapause programming includes an increase of juvenile hormone (JH) titer in the hemolymph from about 20 to 50 nM in the 4th and 5th instar larvae (titer in earlier instars was not measured). JH I, II, and III are present in approximate ratio 1-2:10:1. The JH titer drops to zero before pupation but remains around 20 nM during diapause. Perfect extra larval molts associated with a body weight increase can be induced in the non-diapausing larvae with a JH analogue (JHA). The weight rise is due to accumulation of reserves and not to a general body growth. The timing of extra molts is similar to the molting pattern of the diapausing larvae only when JHA is present since early larval instars. In the diapausing larvae, JHA application affects neither molting periodicity nor the body weight. It is concluded that (1) Increased JH titer in early larval instars is a part of diapause programming; (2) The extension of larval stage in the diapausing larvae, but not the timing pattern of extra molts, is due to continuously high JH titer; (3) The diapause program includes low food intake, maintenance of a certain body weight, and periodic larval molts.     

Developmental strategy of the endoparasite Xenos vesparum (strepsiptera, Insecta): host invasion and elusion of its defense reactions

To successfully complete its endoparasitic development, the strepsipteran Xenos vesparum needs to elude the defense mechanisms of its host, the wasp Polistes dominulus. SEM and TEM observations after artificial infections allow us to outline the steps of this intimate host-parasite association. Triungulins, the mobile 1st instar larvae of this parasite, are able to "softly" overcome structural barriers of the larval wasp (cuticle and epidermis) without any traumatic reaction at the entry site, to reach the hemocoel where they settle. The parasite molts 48 h later to a 2nd instar larva, which moves away from the 1st instar exuvium, molts twice more without ecdysis (a feature unique to Strepsiptera) and pupates, if male, or develops into a neotenic female. Host encapsulation involves the abandoned 1st larval exuvium, but not the living parasite. In contrast to the usual process of encapsulation, it occurs only 48 h after host invasion or later, and without any melanization. In further experiments, first, we verified Xenos vesparum's ability to reinfect an already parasitized wasp larva. Second, 2nd instar larvae implanted in a new host did not evoke any response by hemocytes. Third, we tested the efficiency of host defense mechanisms by implanting nylon filaments in control larval wasps, excluding any effect due the dynamic behavior of a living parasite; within a few minutes, we observed the beginning of a typical melanotic encapsulation plus an initial melanization in the wound site. We conclude that the immune response of the wasp is manipulated by the parasite, which is able to delay and redirect encapsulation towards a pseudo-target, the exuvia of triungulins, and to elude hemocyte attack through an active suppression of the immune defense and/or a passive avoidance of encapsulation by peculiar surface chemical properties.     

Effects of ecdysteroid agonist RH-2485 reveal interactions between ecdysteroids and juvenile hormones in the development of Sesamia nonagrioides

Larvae of Sesamia nonagrioides developing under long day (LD) conditions pupate in the 5th or 6th instar, whereas under the short day (SD) conditions, they undergo several supernumerary larval molts and are regarded as diapausing. The development in early larval instars occurs in the LD larvae at a moderate and in the SD larvae at a high juvenile hormone (JH) titer; ecdysteroid titer cycles similarly under both conditions. The transformation to pupa is initiated by a burst of ecdysteroids at undetectable JH levels, whereas extra larval molts in the diapausing larvae are associated with moderate JH titer and irregular rises of ecdysteroids. Application of 0.2 ppm RH-2485 to the diet of the 6th instar larvae promotes hormonal changes supporting metamorphosis in the LD larvae and slightly accelerates larval molts in the diapausing SD larvae. The 0.5- and 1-ppm doses revert these patterns of endocrine regulations to a mode typical for early larval instars. Particularly dramatic is a JH titer increase provoked within 24 h in the LD larvae. After the treatment, both the LD and SD larvae undergo a series of larval molts, suggesting that hormonal programming of the larval development has been stabilized. A few insects receiving 1 ppm RH-2485, and a high proportion of those fed with 5 ppm RH-2485, deposit two cuticles within a single apolysis and die.     

Mandibular glands in the endoparasitic larva of Uropsylla tasmanica Rothschild (Siphonaptera : Pygiopsyllidae)

An histological study of flea larvae was carried out in order to compare free-living, larvae with the unique endoparasitic larva of Uropsylla tasmanica Rothschild (Siphonaptera : Pygiopsyllidae), a species confined to dasyurid hosts in Tasmania and Victoria, Australia. The free-living species examined were Ctenocephalides felis Bouché (Siphonaptera : Pulicidae) and Odontopsyllus quirosi Gil Collado (Siphonaptera : Leptopsyllidae). Mandibular glands are present in 1st and 3rd instar U. tasmanica, but are absent from 2nd and 3rd instar O. quirosi and all larval instars of C. felis. Such glands in flea larvae have not beeb described previously and they appear to be unique to the endoparasitic U. tasmanica larva. Their presence during the 3rd instar as well as in the 1st instar suggests that although it is possible they play a role in the initial penetration of host skin by the newly hatched larva, they are active in secretion also during the time when the larvae are feeding on host tissue within the dermis.     

Vestigial ophiopluteal structures in the lecithotrophic larvae of Ophionereis schayeri (Ophiuroidea)

Evolution of echinoderm development from a feeding to a non-feeding mode can be examined by studying non-feeding larvae with structures that appear to be vestiges derived from a feeding ancestral state. The lecithotrophic larvae of the Australian brittle star Ophionereis schayeri possess such features, and the early development of this species was documented by light and scanning electron microscopy. The embryos undergo irregular cleavage, resulting in the formation of different sized blastomeres, with subsequent development through a wrinkled blastula stage. The lecithotrophic larva of O. schayeri possesses several vestigial ophiopluteal structures, including a continuous ciliated band, a larval gut, and a larval skeleton. The ciliated band is a reduced expression of the continuous ciliated band typical of ophioplutei. The larval gut is a transiently complete system, but an esophageal plug and rapid closure of the blastopore renders it nonfunctional. The larval skeleton, though reduced, consists of four rods corresponding to the body, posterolateral, anterolateral, and postoral rods characteristic of an ophiopluteus. Due to a heterochrony in larval skeletogenesis, the postoral rods develop early and simultaneously with the other rods. Compared with the larvae of other lecithotrophic ophiuroids, the larva of O. schayeri is one of the most reduced ophiopluteal forms reported to date.     

Brain-independent development in the moth Sesamia nonagrioides

The caterpillars of Sesamia nonagrioides developing under long-day (LD) photoperiod pupate in the 5th or 6th instar whereas under short day (SD) conditions they enter diapause and undergo several extra larval molts. The diapause is terminated within 1-3 instars upon transfer of SD larvae to the LD conditions. Brain removal from the 6th instar larvae promotes pupation followed by imaginal development; however, one third of the SD larvae and 12% of the LD larvae debrained at the start of the instar first undergo 1-2 larval molts. The incidence of larval molts is enhanced by the brain implants. Exclusively pupal molts occur in the LD larvae debrained late in the 6th instar. Decapitation elicits pupation in both LD and SD larvae, except for some of the 4th and 5th and rarely 6th instar that are induced to a fast larval molt. The pupation of decapitated larvae is reverted to a larval molt by application of a juvenile hormone (JH) agonist. No molts occur in abdomens isolated from the head and thorax prior to the wandering stage. Abdomens isolated later undergo a larval (SD insects) or a pupal (LD insects) molt. Taken together the data reveal that in S. nonagrioides (1) several larval molts followed by a pupal and imaginal molt can occur without brain; (2) an unknown head factor outside the brain is needed for the pupal-adult molt; (3) brain exerts both stimulatory and inhibitory effect on the corpora allata (CA); (4) larval molts induced in CA absence suggest considerable JH persistence.     

Mechanism of resistance to the spotted stalk borer,Chilo sacchariphagus,in the sugarcane cultivar R570

Resistance in sugarcane [Saccharum spec. (Poaceae)] to the spotted stalk borer, Chilo sacchariphagus (Bojer) (Lepidoptera: Pyralidae), was studied by comparing feeding behaviour on resistant cv. R570 and susceptible cv. R579. In a field survey, the feeding behaviour of C. sacchariphagus larvae was described to identify their feeding sites on the plant. In a greenhouse artificial infestation study, we compared the establishment of larvae on potted plants. In laboratory choice and no‐choice experiments, we studied the establishment of larvae on plant organs (stalk, sheath, leaf spindle). Study of the feeding behaviour showed that: (1) first to fourth instars are able to feed on stalk, sheath, and leaf spindle, (2) boring into the stalk occurs mostly in the four uppermost internodes, and (3) most young larvae bore through the abaxial surface of leaf sheaths to reach the stalk. In greenhouse experiments, we observed an early two‐fold reduction of the number of larvae on R570 plants within the first 48 h after infestation. In laboratory experiments, larval antixenosis was demonstrated at the abaxial surface of R570 leaf sheath, but was observed neither in the leaf spindle nor in the stalk. First, second, and third instars were susceptible to this antixenosis. We hypothesize that the main resistance mechanism in R570 is an early reduction of larval establishment on plants, due to antixenosis located at the abaxial surface of leaf sheaths.     

Self-selection and utilization efficiency of Heliothis zea larvae feeding on seeds and the walls of snap bean pods

First instar Heliothis zea larvae tended to feed on the leaves of snap beans, but later instars preferred to burrow in the pods. Fifth instars offered only leaves grew poorly because they ate them in small quantities, presumably because of deterrency. The utilization efficiency and growth of fifth instars fed pulp was slightly but significantly inferior to that of seed-fed larvae but was greatly superior to that of leaf-fed larvae. Since the dry matter content of pulp is less than one-third that of seeds, larvae allowed to eat only pulp had abnormally large fresh weight intakes and devoted about three times as much time to feeding as did seed-fed larvae. Larvae offered a mix of seeds and pulp ate both and had a total fresh weight food intake somewhat greater than that of seed-fed larvae but much less than that of pulp-fed larvae. Eating both seeds and pulp offers no obvious nutritional advantage but presumably offers a significant ecological advantage. It is argued that the number of foraging trip a larva must make to discover pods is minimized by feeding on a mix, thus reducing exposure to mortality factors such as predation.     

Oviposition,larval survival and leaf damage by the willow leaf blotch miner,Micrurapteryx salicifoliella,in relation to leaf trichomes across 10 Salix species

1. Foliar trichomes clearly reduce chewing damage and efficiency of movement by some insect herbivores, but the effect of trichomes on insect oviposition is less well characterised. Trichomes are likely to have particularly strong, negative effects on species that require secure attachment of the egg to the leaf epidermis for successful transition to the feeding stage – a group that includes many leaf mining insects. 2. One such species, Micrurapteryx salicifoliella, must initially enter leaf cells directly from an egg adhered to the cuticle, but later instars can move between leaves and initiate new mines from the leaf exterior. 3. Natural patterns of occurrence by M. salicifoliella were quantified on 10 sympatric Salix species varying in trichome expression to test whether trichomes were associated with reduced oviposition, larval survival and leaf damage. 4. Mean egg density and leaf mining damage were negatively related to mean trichome density across Salix species. Survival of M. salicifoliella from egg to pupa was positively related to trichome density, suggesting that initiation of new mines by late‐instar larvae was not adversely affected by trichomes. There was no evidence that trichomes benefited leaf miner larvae indirectly by decreasing density‐dependent mortality; rather, the positive relationship between trichome density and larval survival may reflect less effective chemical defence by Salix species expressing high trichome density. 5. The results suggest that foliar trichomes serve as an effective defence against M. salicifoliella by deterring oviposition, but do not reduce the survivorship of those individuals that successfully transition from egg to larva.     

Hostplant,larval age,and feeding behavior influence midgut pH in the gypsy moth (Lymantria dispar)

Summary The midgut pH of late instar gypsy moth (Lymantria dispar L.) larvae is strongly alkaline, and varies with diet, larval stadium, and time since feeding. Midgut pH rises with time since feeding, and does so more quickly, reaching greater maximum values, on some diets than others. Leaf tissues of 23 tree species resist increases in alkalinity differentially; this trait and differing initial leaf pH may explain the impact of diet on gut pH. Third instar larvae may have gut conditions favorable for tannin-protein binding shortly after ingesting certain foods, but with time midgut alkalinity becomes great enough to dissociate tannin-protein complexes. Older instars rarely exhibit gut pHs low enough to permit tannin activity. Alkaline gut conditions may explain the gypsy moth's ability to feed on many tanniniferous plant species, especially in later instars. Consequences for pathogen effectiveness are discussed.     

Loss of larval parasitism in parasitengonine mites

Larval Parasitengona are typically parasites, yet at least 29 species of water mites and one species of Trombidiidae forgo larval feeding and any association with a host. Species with non-feeding larvae are isolated cases within species groups or genera where the remaining species have parasitic larvae. Species without larval parasitism occur in at least 14 genera, eight families and four superfamilies of water mites; the loss of larval parasitism is presumably polyphyletic, having occurred at least 21 times. Lineages of water mites with non-feeding larvae frequently exist in parallel with almost identical populations or species that have parasitic larvae. Thus, there is tremendous potential for studies comparing the relative merits of the two life history strategies. Comparisons indicate that adults from lineages with non-parasitic larvae produce smaller numbers of larger eggs; the extra nutrition included in larger eggs permits the larvae to forgo feeding. Non-feeding larvae frequently have wider dorsal plates but reduced leg length, setal length and sclerotization when compared to parasitic larvae from sister lineages. The adults of lineages with non-feeding larvae are frequently smaller in comparison to adults of sister lineages with parasitic larvae. There is no apparent pattern in relation to habitat: lineages lacking larval parasitism occur in streams, temporary ponds and the littoral and planktonic regions of permanent lakes. © Rapid Science Ltd. 1998     

Nitrogen fertilization rate affects feeding, larval performance, and oviposition preference of the beet armyworm, Spodoptera exigua, on cotton

Nitrogen (N) is one of the most critical chemical elements for plant and animal growth, exerting a variety of bottom‐up effects. Development and oviposition of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), were studied in relation to varying N fertilization levels (42, 112, 196, and 280 p.p.m.) in cotton [Gossypium hirsutum L. (Malvaceae)]. Low N fertilization of cotton plants led to reduced plant biomass and a lower percentage of N in leaf blades and in leaf petioles. Development of S. exigua larvae fed with plants with reduced N applications (42 and 112 p.p.m.) was prolonged relative to treatments receiving higher N fertilization. Almost all larvae reared on artificial diets underwent only five instars before pupation. However, most larvae reared on cotton plants, irrespective of N levels, experienced a supernumerary sixth larval instar. Furthermore, significantly more larvae reared on lower N cotton plants underwent supernumerary development compared to larvae reared on higher N cotton plants. Life‐time feeding damage per larva ranged from 55 to 65 cm², depending on the nutritional quality of the food plant, although the differences were not statistically significant. Larvae distinguished between cotton plants with various nutritional qualities and fed preferentially on higher N plants. Female moth oviposition choice was also affected by host plant nutritional quality: cotton plants with higher N levels were preferentially chosen by S. exigua females for oviposition. The mechanisms of these effects are unclear, but they can have important implications for population dynamics and pest status of beet armyworms in the field.     

Evidence for the presence of a threshold weight for entering diapause in the yellow-spotted longicorn beetle, Psacothea hilaris

Under long-day conditions larvae of Psacothea hilaris (Coleoptera: Cerambycidae) pupate after the 4th or 5th instar, while under short-day conditions they undergo 2-4 nonstationary supernumerary molts and eventually enter diapause. To explore the possibility of a threshold weight for entering diapause, P. hilaris larvae were deprived of food on days 0 (day of ecdysis), 4 or 8 of the 4th, 5th and 6th instars under short-day conditions. Within the first 40 days of starvation, 60% of the larvae starved starting on day 0 of the 4th instar died, but all the larvae starved at later stages survived. The incidence of diapause in these survivors was determined by the occurrence of pupation after a temporary chilling at 15 degrees C for 15 days. Diapause incidence increased as the onset of starvation was delayed; from 11% in the larvae starved on day 0 of the 5th instar to 100% in the larvae starved on day 4 and day 8 of the 6th instar. Analysis of the relationship between the initial weight of a respective larva at the onset of starvation and its pupation success revealed that none of the larvae weighing 690 mg did. This finding suggests the presence of a threshold weight (about 600 mg), below which larvae are incapable of entering diapause. We discuss these findings with reference to the life history of P. hilaris.     

Caste morphology and development in Termitogeton nr. planus (Insecta,Isoptera, Rhinotermitidae)

The termite family Rhinotermitidae displays a wide diversity in its patterns of social organization in castes. The genus Termitogeton probably branched off early in the evolution of this family. We studied the developmental pathways of a putative undescribed species from New Guinea, Termitogeton nr planus. The development begins with two white inactive instars (larvae), the second of which possesses small wing buds. These are followed by a relatively homogenous group of active immature stages (pseudergates) among which a biometric study revealed the presence of four instars. The first of these instars possesses wing buds that regress at subsequent molts. The external morphology of older instars resembles that of higher termite workers. Older pseudergates can differentiate into presoldiers and then into soldiers, but they are also able to molt into a unique stage with long wing pads (nymph), preceding the imago. Colony maturity can be reached with about 10(3) individuals. The sex ratio is near 1:1 in all castes except soldiers, among which females are more numerous than males. The caste pattern of T. nr. planus is reminiscent of those of the Kalotermitidae and Termopsidae, and of Prorhinotermes among the Rhinotermitidae. None of these taxa possess a true worker caste, permanently diverted from imaginal development: social tasks are done by unspecialized immatures that retain a full array of developmental options, including that of proceeding to the imago. The most remarkable trait of T. nr. planus is the presence in all second-instar individuals of wing buds that later regress to reappear in the single nymphal stage. We suggest that the traditional definitions of the terms larvae, nymphs, and pseudergates should be revised because they cannot be satisfactorily applied to the castes of Termitogeton.     

A new Brazilian Passiflora leafminer: Spinivalva gaucha,gen. n., sp. n. (Lepidoptera,Gracillariidae, Gracillariinae), the first gracillariid without a sap-feeding instar

Male, female, pupa, larva and egg of a new genus and species of Gracillariidae (Gracillariinae), Spinivalva gaucha Moreira and Vargas from southern Brazil are described and illustrated with the aid of optical and scanning electron microscopy. A preliminary analysis of mitochondrial DNA sequences including members of related lineages is also provided. The immature stages are associated with Passiflora actinia, Passiflora misera and Passiflora suberosa (Passifloraceae), and build mines on the adaxial leaf surface. Initially the mines are serpentine in shape, but later in larval ontogeny become a blotch type. Although the larvae are hypermetamorphic as in other Gracillariidae, there is no sap-feeding instar in Spinivalva gaucha; the larva feeds on the palisade parenchyma, thus producing granular frass during all instars. Pupation occurs outside the mine; prior to pupating, the larva excretes numerous bubbles that are placed in rows on the lateral margins of the cocoon external surface. This is the second genus of gracillariid moth described for the Atlantic Rain Forest, and the second gracillariid species known to be associated with Passifloraceae.     

褐边绿刺蛾的取食行为和取食量

观察褐边绿刺蛾Parasa consocia Walker2个世代幼虫取食杨树叶片的习性。结果表明,第1代幼虫7龄,幼虫期平均取食量167.7cm2/头,取食持续时间26d;第2代幼虫8龄,幼虫期平均取食量170.5cm2/头,取食持续时间27d。2个世代末龄幼虫取食量最大,占整个取食量的80%左右,4~5龄幼虫是防治的关键龄期。     

Changes in levels of juvenile hormone and molting hormone in larvae and adult females of Chilo suppressalis (Lepidoptera: Pyralidae) after imidacloprid applications to rice

Insect hormones regulate growth and development and fecundity of insects. The current study investigated changes in juvenile hormone (JH) and molting hormone (MH) levels in fourth instars and adult females of Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) after imidacloprid application to rice, Oryza sativa L. The results showed that JH level in fourth instars that developed feeding on Fengyouxiangzhan rice plants sprayed with 15, 30, and 60 ppm imidacloprid was significantly higher than that of larvae that developed on control plants, increasing by 5.04, 6.39, and 4.89 times, respectively. The relationships between JH level and imidacloprid concentrations showed a significant negative correlation. In contrast, molting hormone (MH) level in larvae fed on control plants was significantly higher than that on treated plants. JH:MH values in fourth instars developed from larvae feeding on rice plants treated with 15, 30, 60, 80, and 100 ppm imidacloprid increased by 49.17, 39.43, 13.48, 15.80, and 0.2 times, respectively, compared with control. JH and JH:MH ratio in larvae fed on Wujing 15 plants treated with imidacloprid were significantly lower than those fed on Fengyouxiangzhan under the same treatments. JH level in adult females that developed from larvae feeding on rice plants sprayed with imidacloprid significantly decreased with increase in imidacloprid concentration, but it increased compared with control. JH level in adult females was associated with times of imidacloprid application. JH level in adult females developed from larvae feeding on rice plants after double spray with 30 ppm imidacloprid was significantly higher than control, increasing by 61.6 and 116.5%, respectively, compared with a single spray and the control. Moreover, hormone levels in the larvae were related to the application method of imidacloprid. JH level in fourth instars after root application and topical application of imidacloprid was significantly lower than in control. Thus, the dynamics of JH and MH in insects after insecticide applications are an extremely interesting problem, because hormones are related to insect growth and development.     

Predatory wasps learn to overcome the shelter defences of their larval prey

Larvae of Epargyreus clarus (Hesperiidae), the silver-spotted skipper, inhabit leaf-and-silk shelters that they construct on their leguminous host plants. In the field, Polistes spp. (Vespidae) wasps land on the shelters, quickly extracting and killing the larvae within. In marked contrast, wasps that emerge from field-collected colonies maintained in the laboratory visit and examine leaflets bearing sheltered caterpillars, but only rarely do they extract and kill the sheltered larvae. To examine whether learning is involved in the development of the ability of Polistes wasps to forage successfully on sheltered E. clarus larvae, we tested the responses of P. fuscatus and P. dominulus wasps to sheltered E. clarus larvae before and after their exposure to unsheltered larvae that were visible either on an opened host-leaf shelter (P. fuscatus and P. dominulus) or on a nonhost leaf in the absence of a shelter (P. fuscatus). After killing and processing an unsheltered larva that was visible on an opened leaf shelter, a majority of foragers subsequently extracted and killed larvae from closed shelters. Wasps that killed and processed an unsheltered larva on a nonhost leaf, on the other hand, generally did not later open shelters. Thus, it seems that experience with an exposed larva in the context of its shelter is necessary for a wasp to be able to prey on sheltered larvae. We conclude that the wasps must learn to associate the taste of the larva with shelter-related cues, such as presence of leaf damage and silk. In nature, this initial exposure may occur when the larva is visible in or near its shelter, perhaps when feeding or constructing a new shelter. Learning opportunities will thus depend on larval density. Our results show that invertebrate predators can learn to overcome their prey's defences, and are therefore able to make use of previously inaccessible prey.     

A biological assessment of Apophua simplicipes (Hymenoptera: Ichneumonidae) as a parasitoid of the oblique banded leafroller, Choristoneura rosaceana (Lepidoptera: Tortricidae)

Apophua simplicipes (Cresson) (Hymenoptera: Ichneumonidae) is a common parasitoid of the oblique banded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) in organically managed apple orchards in the southern interior of British Columbia, Canada. The biological characteristics of a laboratory colony of A. simplicipes were studied. When held at 15 and 25°C and provided with honey water, individual females survived an average of 60.6±6.1 and 29.8±4.7 days, oviposited 196.7±50.7 and 326.6±51.3 eggs and parasitized a total of 163.4±40.4 and 229.4±35.8 hosts, respectively. Females oviposited into first through fourth instar oblique banded leafrollers, with significantly more parasitism occurring in the first two instars compared to the third and fourth instars. No parasitoid larvae survived past the first larval stage in parasitized fourth instar hosts. Apophua simplicipes did not parasitize larvae of three-lined leafroller, Pandemis limitata (Robinson) (Lepidoptera: Tortricidae) which is sympatric with oblique banded leafrollers in orchards in the southern interior of British Columbia. Female predation and host feeding from wounds on early instars of both leafroller species was observed under laboratory conditions. In addition, early instar hosts exited diet feeding sites in response to the probing activity of the ovipositing wasps. A similar escape reaction in the orchard may cause a leafroller larva to move away from its feeding site, making it more vulnerable to predation or movement off the tree. Apophua simplicipes larvae emerged from fifth and sixth instar hosts. Parasitized oblique banded leafroller hosts consumed significantly less meridic diet than unparasitized female larvae from fifth instar through to parasitoid emergence or leafroller pupation. Our laboratory results suggest that A. simplicipes may reduce field populations of oblique banded leafroller and decrease pest feeding damage.