Morphogenetic and physiological effects of a juvenile hormone analogue on the light brown apple moth,Epiphyas postvittana (Lepidoptera: Tortricidae)

Abstract

The juvenile hormone analogue ZR-619—ethyl 11-methoxy-3,7,11-trimethyl-(2E,4E-dodecadienethiolate) —produced morphological and physiological effects when fed via artificial diet to larvae of Epiphyas postvittana (Walker). Morphological effects included changes in larval head and antennal structures after instar V (supernumerary instars); deformation of pupal and adult structures, particularly in genitalia and wings; and development of individuals with varying mixtures of larval and pupal structures. Physiological effects included prolongation of larval life, increase in larval weight, increase in larval instars, and decrease in fecundity. Effects were directly related to dosage concentrations.     

The description of immature forms of Aphropsyche monticola flint (Trichoptera: Hydropsychidae)

Abstract

Several larval, pupal, and adult specimens of Aphropsyche monticola Flint were collected from a locality in Pennsylvania. Examination of this material led to the association of the immature forms of the genus Aphropsyche by the metamorphotype method. The larvae will key to Aphropsyche? in Wiggins (1977), who has tentatively assigned the larval form of this genus.     

Note on the life history of the magpie moth,Nyctemera annulata (Lepidoptera: Arctiidae)

Nyctemera annulata Boisduval was reared in the laboratory at 26±1°C and 50 ±5% RH on a host plant, ragwort (Senecio jacoboea L.), and on an artificial diet. On ragwort the average life cycle of 34 days embraced a larval period of 24 days, with up to 6 larval instars, and a pupal period of 9–11 days, depending on whether pupation occurred at the 5th or 6th instar. On the artificial diet the larval period of 56 days, involving up to 10 instars, was followed by a pupal period of 9 days, for an average life cycle of 65 days.     

Growth regulatory and growth inhibitory effects of Thevetia neriifolia stem extracts on Helicoverpa armigera (Lepidoptera: Noctuidae)

Abstract

Helicoverpa armigera, a serious global destructive pest of agricultural crops, is on continuous rise despite several control measures undertaken. The detrimental effects of these measures have created a dire need to explore alternate eco-safe strategies. The present study investigates the growth-regulatory and growth-arrest potential of hexane and methanol extracts of Thevetia neriifolia stems against H. armigera. Investigations revealed that larval feeding and rearing on the extract-containing diet did not result in appreciable larval mortality but delayed the larval growth and development. Both the extracts demonstrated dose-dependent effects exhibiting negative correlation between the weights gained by developmental stages and the extract concentrations. Feeding with extracts also resulted in formation of few larval–pupal and pupal–adult intermediates and significantly reduced percent adult emergence of H. armigera. Current study, however, revealed higher growth inhibitory potential of methanol extracts as compared with hexane extracts. The study attempts to provide an eco-friendly approach for H. armigera management.     

An artificial diet for larvae of the potato tuber moth

Potato tuber moth, Phthorimaea ( = Gnorimoschema) operculella (Zeller) (Lepidoptera: Gelechiidae), was reared from egg to adult for 3 generations on an artificial diet. At 30±2°c with a 16‐h photoperiod the total life cycle was completed in 23 days, compared with 18.5 days on potato tubers. Average life cycle data from the 3 generations reared on diet (with corresponding data from tubers in parentheses) are: larval period, 13.0(11.8) days; pupal period, 5–6(4–5) days; survival to adult, 76.1(100)%; fecundity, 102(169) eggs/?; pupal wt‐ ? 8.3(11.4) mg, ? 7.7(9.1) mg.     

Reinstatement of a New Zealand copper butterfly,Lycaena rauparaha (Fereday, 1877)

Abstract

Previous confusion over the nomenclature and status of the New Zealand copper butterflies is reviewed. Lycaena rauparaha n. comb., which has been regarded as a variety of L. salustius in recent literature, is reinstated and adult, larval, and pupal characters are described. Its distinctions from L. salustius and L. feredayi are tabulated and a key to this species complex is given.     

Seasonal phenology and stage-specific parasitism of the apple ermine moth, Yponomeuta malinellus Zeller, in Korea

The apple ermine moth, Yponomeuta malinellus Zeller (Lepidoptera: Yponomeutidae), is a tent caterpillar that feeds on Malus spp. in Korea. Populations of the moth in native areas appeared to be regulated by the assemblage of parasitoids. Phenological associations between host stages and parasitoids, susceptible stage(s) of the host for each parasitoid, and stage‐specific parasitism were studied. The egg larval parasitoid Ageniaspis fuscicollis (Dalman) had highest parasitism of first instar larvae (24%), with 14% parasitism of other larval stages. Dolichogenidea delecta (Haliday) was recovered from all larval instars with the highest parasitism rate of second instar larvae (20.1%), followed by 19.9% parasitism of mid‐larval hosts. Herpestomus brunicornis Gravenhorst was reared from second instar larvae through to pupal collection, and had the highest parasitism rate (29.9%) at the pupal stage. The larval pupal parasitoid Zenillia dolosa (Meigen) was recovered from mid‐larval to pupal stages with the highest parasitism rate (5.5%) occurring in third to fourth instar larvae. The host stages for developing A. fuscicollis completely overlap with those of D. delecta, and with those of H. brunicornis to some degree. A statistically significant negative correlation exists between A. fuscicollis and these dominant parasitoids, indicating competitive interaction within the host.     

The toxicity and biological effect of Pedalium murex L. extracts on the tobacco cutworm,Spodoptera litura (Fabr.) larvae

Petroleum ether, acetone, water and aqueous extract of Pedalium murex L. (Pedalaceae) leaves, root and fruit were tested against fourth instar larvae of the tobacco cutworm, Spodoptera litura (Fabr.) under laboratory conditions using leaf dip method. Larval mortality; larval, pupal and adult periods; pupal weight, pupation and adult emergence; larval and pupal deformities of S. litura were recorded. All the tested solvent extracts of P. murex were effective against S. litura life stages by causing mortality in a dose dependent manner. However, the efficacy was more significant with respect to acetone (leaf and root) and petroleum ether (root) at higher concentrations (0.8%) which leads to 100% larval mortality. The water and aqueous extracts of root caused 86.6 and 88.0% larval mortality respectively at 4% concentration. Among the plant parts tested, root had more importance followed by leaf and fruit. Plant extracts extended the larval, pupal and adult periods; reduced the pupal weight, pupal and adult emergence and caused larval–pupal deformities. Total life time was highly prolonged in acetone extracts of P. murex root. Though all the extracts were found to have insecticide activity, acetone and petroleum ether extracts of P. murex root can be used as an effective alternative to modern synthetic insecticides. Bioactive principles from these extracts can be isolated, identified and integrated in S. litura management.     

Reassessment of the enigmatic Lepidopteran family Lypusidae (Lepidoptera: Tineoidea; Gelechioidea)

Abstract. The genus Lypusa Zeller, 1852 has been assigned to Tineoidea (Lepidoptera) with varying family positions. The systematic affinities of this genus, currently placed in its own family Lypusidae, were studied using extensive data derived from larval, pupal and adult morphology and certain behavioural traits. In total, 193 characters were considered. On the basis of the results of a parsimony analysis, Lypusa is transferred to the superfamily Gelechioidea, in a monophyletic, exclusively Palaearctic assemblage with the genera Amphisbatis and Pseudatemelia. Several phylogenetically relevant characters support this position, including similarly constructed larval cases, densely porose larval head, and a modification of the pupal abdominal segment 8. The composition of the family Amphisbatidae is discussed and it is proposed that it be delimited as comprising solely the Palaearctic genera Pseudatemelia, Amphisbatis and Lypusa. A detailed diagnosis of the genus Lypusa is given.     

LARVAL AND PUPIL BEHAVIOUR IN CULISETA LONGIAREOLATA (MACQUART, 1838) (CULICIDAE,DIPTERA)

SUMMARY

Six larval and two pupal activities could be distinguished. The larval activities are medium filter-feeding (MFF), surface filter-feeding (SFF), browsing and gnawing (BRG), swimming (SS), surface hanging (HA) and grooming (GR). The pupal activities are limited to surface hanging (HA) and swimming (SS). The percentage value of each activity from eclosion to emergence of the adults was established by means of a six-channel manual recorder. In larvae HA is the predominant activity, shows an inverse relation with all other activities, and attains peak percentage values prior to each ecdysis. BRG is the most important method of feeding, and is followed by MFF and then by SFF in order of importance. SS accounts for a low percentage value. Initially it is depth-independent in first stage larvae, but later becomes depth-dependent. In pupae the HA percentage values are high, since the pupal stage is a period of quiescence. The SS percentage values are very low and could have been escape reactions to extraneous stimuli. No circadian rhythm could be detected in any of the activities.     

Use of day-degree estimates for rearing management of Ctenopseustis obliquana (Lepidoptera: Tortricidae) in the laboratory

Abstract

The brownheaded leafroller (BHLR), Ctenopseustis obliquana (Walker) (Lepidoptera: Tortricidae) was reared on an artificial diet at seven constant temperatures. The mean life cycle at optimum rearing temperature of 20 ± 1°C was: egg development 8.7 days; larval period, M 37.4, F 41.2 days; pupal period, M 14.9, F 13.3 days; pupal weights, M 50.5, F 68.2 mg; and a fecundity of 670 eggs per female. Estimated lower threshold temperatures and mean cumulative number of day- degrees for various stages of development were 7.8°C and 105D° for eggs, 5.2°C and 538D° for larvae, and 7.2°C and 186D° for pupa. Total mean day-degree accumulation from egg to adult was 829D°.

These data were used to develop an efficient rearing management system embracing colony maintenance, storage, manipulation, production, and quality assessment procedures.     

Temporal programming of epidermal cell protein synthesis during the larval-pupal transformation ofManduca sexta

Summary During the final larval instar the epidermis of the tobacco hornworm,Manduca sexta, synthesizes the larval cuticular proteins and the pigment insecticyanin. Then at the onset of metamorphosis the cells first become pupally-committed, then later produce the pupal cuticle. The changes in the pattern of epidermal protein synthesis during this period were followed by incubating the integument in vitro with either³H-leucine or³⁵S-methionine, then analyzing the proteins by 2-dimensional gel electrophoresis. Precipitation by larval and pupal cuticular antisera and by insecticyanin antibody identified these proteins. Three distinct changes in epidermal protein synthesis were noted: 1) Stage-specific proteins, some of which are larval cuticular proteins, appear just before and during the change of commitment on day 3. (2) By late the following day (wandering stage), synthesis of these and many other proteins including all the identified larval cuticular proteins and insecticyanin was undetectable. Several noncuticular proteins were transiently synthesized by this pupally committed cell during wandering and sometimes the following day. (3) During the production of pupal cuticle a new set of pupal-specific cuticular proteins as well as some common cuticular proteins (precipitated by both antisera) were synthesized. Some of the latter were also synthesized during the period between pupal commitment and pupal cuticle deposition.In spite of an apparent absence of methionine in both larval and pupal cuticle, many cuticular proteins incorporated³⁵S-methionine. Thus they may be synthesized as proproteins.Insecticyanin was shown to have two forms differing in isoelectric point, the cellular form being more acidic than the hemolymph form. Synthesis of the cellular form ceased before that of the hemolymph form.     

Laboratory rearing method for the stem weevil,Hyperodes bonariensis (Coleoptera: Curculionidae)

The stem weevil, Hyperodes bonariensis Kuschel, was reared from egg to adult for eight generations on an artificial medium. At 26±0.5°C, 55±5% RH, and 12‐h photo‐period, development time from newly hatched larva to adult averaged about 28 days. There were four larval instars lasting about 14 days, followed by prepupal and pupal stages lasting a further 14 days. Oviposition occurred 2 weeks after adult emergence; mated females laid viable eggs. Ovarian diapause in some females was also noted. It is possible to rear about six generations a year under these conditions.     

The proprotein convertase amontillado (amon) is required during Drosophila pupal development

Peptide hormones governing many developmental processes are generated via endoproteolysis of inactive precursor molecules by a family of subtilisin-like proprotein convertases (SPCs). We previously identified mutations in the Drosophila amontillado (amon) gene, a homolog of the vertebrate neuroendocrine-specific Prohormone Convertase 2 (PC2) gene, and showed that amon is required during embryogenesis, early larval development, and larval molting. Here, we define amon requirements during later developmental stages using a conditional rescue system and find that amon is required during pupal development for head eversion, leg and wing disc extension, and abdominal differentiation. Immuno-localization experiments show that amon protein is expressed in a subset of central nervous system cells but does not co-localize with peptide hormones known to elicit molting behavior, suggesting the involvement of novel regulatory peptides in this process. The amon protein is expressed in neuronal cells that innervate the corpus allatum and corpora cardiaca of the ring gland, an endocrine organ which is the release site for many key hormonal signals. Expression of amon in a subset of these cell types using the GAL4/UAS system in an amon mutant background partially rescues larval molting and growth. Our results show that amon is required for pupal development and identify a subset of neuronal cell types in which amon function is sufficient to rescue developmental progression and growth defects shown by amon mutants. The results are consistent with a model that the amon protein acts to proteolytically process a diverse suite of peptide hormones that coordinate larval and pupal growth and development.     

Host range of the leaf-tier Tentamen atrivirgulatum Metz (Lepidoptera: Gelechiidae); an unsuitable candidate for biological control of Brazilian peppertree

ABSTRACT

The life history and host range of the South American leaf-tier Tentamen atrivirgulatum Metz, 2019 (Lepidoptera: Gelechiidae) was evaluated to determine its suitability for classical biological control of invasive Brazilian peppertree, Schinus terebinthifolia, in the USA. Larvae were collected during a survey in the native range of Brazil feeding on Brazilian peppertree. A quarantine colony was established and no-choice tests were conducted to determine the host range of this species. The results of these tests indicated that the larvae fed and completed development on seven of the eleven non-target species tested. Percent survival on these non-targets ranged from 20% to 100%. Larval survival was 50% when fed the target weed Brazilian peppertree. When larvae were fed leaves of these non-targets, pupal weights were significantly lower only for those fed Pistacia chinensis. Development time to the pupal and adult stages did not differ with larval diet. These no-choice results indicate T. atrivirgulatum larvae have a broad host range and thus this species will not be developed as a biological control agent for Brazilian peppertree in the USA.     

Sublethal effects of Bacillus thuringiensis on the spruce budworm, Choristoneura fumiferana

Exposing larvae of the spruce budworm, Choristoneura fumiferana (Clemens), to sublethal ( 50% lethal dose) levels of Bacillus thuringiensis subsp. kurstaki at various stages of their development significantly increased development time to the pupal stage and reduced pupal size and number of eggs laid per female, but did not affect the proportion of embryonated eggs. The changes in larval development time, pupal weight and fecundity depended on the larval stage that was treated. Exposure of fourth instars delayed larval development and reduced only male pupal weights with no effects on fecundity. Exposure of sixth instars delayed larval development to a lesser extent than exposure of fourth instars but had a pronounced effect on weight of both male and female pupae. The effect on pupal weight was sex dependent, as males tended to be more affected than females. The reduction in male pupal weight did not appear to influence fecundity, because the effect of exposure was explained by the change in female pupal weight. Effects on larval growth and pupal weight were proportional to the dose that was ingested during exposure, and were observed at doses as low as one-tenth of the LD₅₀. Ingestion of an LD₅₀ caused a 29 or 45% delay in development of, respectively, female or male larvae when exposed as fourth instars and a 30% reduction in female pupal weight when larvae were exposed as sixth instars.     

Effect of plant oils on quality parameters of Bactrocera tryoni (Froggatt) reared on liquid larval diet

Liquid larval diets have been developed for several tephritid fruit flies including Queensland fruit fly, Bactrocera tryoni (Frogatt) (Q‐fly). In liquid diets, wheat germ oil (WGO) is usually added to improve performance in some quality parameters of reared flies, especially flight ability. However, for some flies, other plant oils may be more readily available, cheaper or produce flies of superior performance. In the present study, four alternative types of plant oils – rice bran, canola, vegetable, and sesame – were incorporated into a fruit fly liquid larval diet to replace the currently used wheat germ oil and their efficacy on the quality parameters of reared Q‐fly was compared to diets containing wheat germ oil or no oil. The quality parameters included: total pupal yield (N), pupal recovery (%), larval duration (days), pupal weight (mg), adult emergence (%), adult fliers (%), rate of fliers (%), sex ratio (%), F₁ egg/female/day and egg hatching (%). There were significant differences among treatments in performance of Q‐fly. Vegetable oil appeared better in terms of total pupal yield, percentage of pupal recovery, percentage of adult emergence, percentage of fliers, mean egg/female/day and % F₁ egg hatch compared with other oil treatments, especially from that of WGO treated diet. The result suggests that WGO can be substituted with rice bran and vegetable oil to improve the liquid larval diet for rearing of B. tryoni, with vegetable oil being the best replacement.     

Regulatory mechanisms in phenotypic plasticity of diapause and nondiapause pupal colouration of the swallowtail butterfly Papilio machaon

Nondiapause pupae of Papilio machaon L. exhibit pupal colour diphenism comprising green–yellow and brown–white types. To understand the regulatory mechanism underlying the control of pupal colouration in P. machaon, the effect of environmental cues on diapause and nondiapause pupal colouration is investigated. When larvae reared under short‐day and long‐day conditions are allowed to pupate in sites with a smooth surface and a yellow background colour, all diapause pupae exhibit a brown–white type and 89.5% of nondiapause pupae exhibit a green–yellow type, respectively. With rough‐surface pupation sites, all diapause pupae exhibit brown–white and intermediate types, whereas a large proportion of nondiapause pupae exhibit brown–white and intermediate types, although some exhibit a green–yellow type. When extracts prepared from the head‐thoracic and thoracic‐abdominal regions of larval central nervous systems are injected into the ligated abdomens of P. machaon short‐day pharate pupae, all recipients exhibit a brown–white colouration. Furthermore, when each extract is injected into the ligated abdomen of Papilio xuthus L. short‐day pharate pupae with orange‐pupa‐inducing factor activity, recipients injected with the head‐thoracic extract exhibit the brown type, whereas those injected with the thoracic‐abdominal extract exhibit an orange colour. The results indicate that the response to the environmental cues of pupation site in P. machaon changes according to the photoperiodic conditions experienced during larval stages, and that at least two hormonal factors producing brown–white pupae are located in the larval central nervous system, with the secretion of these factors being regulated by the recognition of environmental cues in long‐day larvae.     

Developmental attenuation of the pre-ecdysis motor pattern in the tobacco hornworm,Manduca sexta

Summary At the culmination of each molt, the larval tobacco hornworm exhibits a pre-ecdysis behavior prior to shedding its old cuticle at ecdysis. Both pre-ecdysis and ecdysis behaviors are triggered by the peptide, eclosion hormone (EH). Pre-ecdysis behavior consists of rhythmic abdominal compressions that loosen the old larval cuticle. This behavior is robust at larval molts, but at the larval-pupal molt the only comparable behavior consists of rhythmic dorso-ventral flexions of the anterior body. These flexions appear to be an attenuated version of the larval pre-ecdysis behavior because (1) they show the same EH dependence, and (2) the motor patterns recorded from EH treated, deafferented larval and pupal preparations are similar except that the pupal pattern is much weaker. Both patterns are characterized by rhythmic, synaptically-driven bursts of action potentials in motoneurons MN-2 and MN-3, which occur synchronously in all segments. However, the synaptic drive to the motoneurons and their resultant levels of activity are reduced during the pupal pre-ecdysis motor pattern, especially in posterior abdominal segments. Although the dendritic arbors of both motoneurons regress somewhat during the larval-pupal transformation, this does not appear to be the primary source of diminished synaptic drive because regression is greatest in the segments in which synaptic inputs remain the strongest. The developmental weakening of the pre-ecdysis motor pattern thus may be due to changes at the interneuronal level.Abbreviations A2, A3... abdominal segments 2, 3, etc. - ALE anterior lateral external muscle - day L3 third day of the 5th larval instar - day P0 the day of pupal ecdysis - DN _a anterior branch of the dorsal nerve - EH eclosion hormone - HPLC high performance liquid chromatography - TP tergopleural muscle     

Descriptions of the previously unknown xylobiont larva and pupa of <Emphasis Type="Italic">Atypophthalmus inustus</Emphasis> (Diptera,Limoniidae)

The larval and pupal morphology of Atypophthalmus inustus (Meigen, 1818) are described for the first time. The main diagnostic characters are the following: head capsule massive, frons with 3 short terminal projections, hypostomium with 11 teeth and long narrow split, hypopharynx and labium with well-developed conical teeth, stigmal area with 2 long ventral pigmented spots.