The larva of the Palaearctic Renocera pallida (Fallén, 1820) is confirmed as a predator of small species of bivalve molluscs of the family Sphaeriidae. To date only the larvae of three Nearctic Renocera species (and larvae of two other species of Sciomyzidae in two genera) are known to have the same food preference. The life cycle, biology, larval feeding and behaviour are described for the first time and compared with that of the Nearctic Renocera. The systematic position and biology of Renocera in general are discussed. Descriptions of the egg, second and third larval instars and the puparium of R. pallida are presented, the main features of the egg and larvae are illustrated by scanning electron micrographs.
This paper describes the first-instar larva of Geocharidius Jeannel, a species from Mexico, which is the second record of an Anillina (Coleoptera: Carabidae: Trechitae) larva; previously described was a species of the European genus Typhlocharis. Larvae of these two genera share ten synapomorphic characters, which support the monophyletic origin of Anillina. Sister-group relationships of Anillina with Tachyina + Xystosomina are proposed on the basis of three shared larval synapomorphies: seta LA5 of ligula absent; coronal suture in first-instar larvae very short or absent; second- third-instar larvae have none or one secondary seta on lateral sides of stipes and labium and none on mandibles.
Larvae of Rhipsideigma raffrayi are described in detail and those of Distocupes varians are re-examined. Their morphological structures are evaluated with respect to their functional and phylogenetic significance. Larvae of Rhipsideigma are wood-borers with a straight body and a wedge-shaped head capsule. Most of their apomorphic features are correlated with their xylobiontic habits. The strong mandibles, the sclerotized ligula and the wedge-shaped head enable the larvae to penetrate rotting wood. The broadened prothorax, prosternal asperities, tergal ampullae, the short legs, and eversible lobes of segment IX play an important role in locomotion in galleries within rotting wood. Leg muscles are weakly developed, whereas the dorsal, pleural and ventral musculature is complex. The larval features allow Rhipsideigma to be placed in the clades Archostemata, Cupedidae + Micromalthidae, Cupedidae, Cupedidae excl. Priacma, and Cupedidae excl. Priacma and Distocupes. The monophyly of Cupedidae and Cupedidae, excluding Priacma, so far is only supported by apomorphies of the adults. However, the presence of glabrous patches on the prosternum and of a medially divided field of asperities may be larval apomorphies of the family. A clade, which comprises Rhipsideigma, Tenomerga and probably other genera of Cupedidae with hitherto unknown larvae, is well supported by larval apomorphies such as the broadened prothorax, the presence of coxal asperities and the presence of a distinct lateral longitudinal bulge. Increased numbers of antennomeres and labial palpomeres are apomorphies only found in larvae of Distocupes.
The three larval instars of Megadytes (M.) carcharias Griffini and M. (Trifurcitus) fallax (Aubé) are described and illustrated in detail for the first time, with an emphasis on morphometry and chaetotaxy of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. The ground plan of chaetotaxy of the genus Megadytes Sharp is described and illustrated based on three of the four recognised subgenera. First-instar larvae of Megadytes are characterised by the presence of a large number of additional sensilla on almost every part of the body. Primary chaetotaxy of the subgenera (Bifurcitus Brinck based on third instar) is very similar, with few differences including (1) shape of the setae on the anterior margin of the frontoclypeus; (2) presence or absence of a ring of multi-branched setae on distal third of mandible; and (3) number of setae on the urogomphus. A cladistic analysis of Dytiscidae, based on 169 larval characters and 34 taxa, indicates that: (1) Trifurcitus Brinck deserves generic status; (2) Cybistrini are not closely related to Hydroporinae; (3) the absence of a galea in Cybistrini is a secondary loss independent of that in Hydroporinae; (4) Cybistrini are well supported by many characters (including several aspects of first-instar chaetotaxy).
The third instar larva of Anacaena cordobana Knisch, and the egg case of Anacaena lutescens (Stephens) are described and illustrated. The taxonomic status of the immature stages of Anacaenini is clarified by comparing their morphology with that described in the literature. Larval descriptions of Anacaena and Paracymus published by Richmond (1920) are interchanged, as are the identifications of all subsequent authors based on Richmond's work. All Anacaenini genera for which larvae are known are diagnosed. A comparative morphological study of Anacaena larvae shows many similarities between Crenitis and Anacaena larvae, suggesting a close relationship between these two genera.
To determine the causes of the variation in the seasonal dynamics of Harmonia axyridis (Pallas) in Central Europe, numbers of adults and larvae of this invasive species were recorded on trees (Acer, Betula, Tilia) throughout the growing seasons from 2011 to 2016. Each year beetles were collected every two weeks, using a standardized sweeping method. The seasonal dynamics was expressed as plots of abundance (number of individuals per 100 sweeps) against time (Julian day) and these plots (seasonal profi les) were compared in terms of their size (area under the seasonal profi le curve), range, timing and height of the mode (maximum abundance). Timing and size of seasonal profi les varied among hostplants, years and sites. Abundance of larvae paralleled aphid occurrence and peak abundance of adults followed that of larvae 10 to 20 days later. Population dynamics before and after the peak were determined by dispersal. Adults arrived at sites before the start of aphid population growth and persisted there long after aphid populations collapsed. The abundance of H. axyridis decreased from 2011 to 2013 and then increased, achieving the previous levels recorded in 2015 and 2016. The variation in seasonal profi les revealed that H. axyridis, in terms of its response to environmental conditions, is a plastic species and this fl exibility is an important factor in its invasive success.
The development stages of a species may have an identical lower development threshold (LDT) and proportionally different durations. This phenomenon called "rate isomorphy" (RI) has been demonstrated for a number of insect species. In contrast, the growing day degrees accumulated over the period of larval development (sum of effective temperatures SET) should be plastic and vary with environment conditions. The prediction from RI is that, with changing conditions, the uniform LDT should be accompanied by differences in development time which remain proportional at different temperatures. This was tested by investigating the effect of diet on thermal requirements for development of larvae of the polyphagous species Autographa gamma (L.) (Lepidoptera: Noctuidae). The larvae were kept at 15.0, 20.3 and 26.7°C and fed on leaves of 13dicotyledoneous herb and tree species. The proportion of total development time spent on a particular diet was plotted against temperature. The existence of RI was inferred from a zero change in development time proportion with changing temperature. This rigorous test supported RI for 3 of 9 diets where development was completed in all temperatures. The LDT observed on 11 diets where the larvae completed development in at least 2 temperatures varied between 9.3 and 11.0°C while SET varied between 167 and 353 day degrees (dd). Assuming RI, LDT and SET for those 9 diets were recalculated. The recalculated LDT was 10.0°C and SET varied between 177-257 dd. The SET increased with decreasing water content and decreasing nitrogen content of food. Worsening food quality decreased food consumption, metabolic and food conversion efficiency, and the relative growth rate of the larvae. Increasing metabolic costs of development were thus positively correlated with SET. The standardized rate of growth (mg.dd-1) was typical for particular diets. Pupal mass decreased with increasing temperature and, within each temperature, with development length.
First instar larvae of Polystoechotidae sp., and first and older instar larvae of Ithone fusca Newman and Oliarces clara Banks are described; those of the latter species for the first time. The family Ithonidae is unique in Neuroptera in having grub-like C-shaped older instar larvae. Potential morphological synapomorphies of mature larvae of Ithonidae and Polystoechotidae are the mandibles with exceptionally broad base and markedly thickened apical part; antennal curvature is fixed and rather characteristic in shape; ocular area reduced or absent; cardo and stipes are markedly enlarged with stipes much larger than the cardo; presence of gula (Polystoechotes) or some traces of gular sclerotisation (Ithone, Oliarces). Larvae of Ithone have numerous larval autapomorphies such as C-shaped first instar larva with reduced abdominal segments IX and X; fused tibia and tarsus on all legs and dorsally directed maxillae. Larvae of Ithonidae and Polystoechotidae have some similarities with those of the family Dilaridae, such as no or one pair of stemmata; body not flattened dorso-laterally; mesothoracic spiracle located on fold between prothorax and mesothorax; short and stout mandibles widened at base and tapered apically; robust and elongated fore legs; tarsi on all legs markedly shortened; more than three larval instars. Older instar larvae of Ithonidae are markedly similar to those of the beetle superfamily Scarabaeoidea in having a C-shaped body, at least in older instars; body round in cross-section; sclerites on thorax and abdomen reduced and body surface membranous; each thoracic and abdominal segment subdivided dorsally into two or three fleshy lobes; ventral surface of abdominal apex bears a field of short and stout setae. Chaetotaxy pattern in first instar Ithonidae and Polystoechotidae larvae suggests that it is possible to homologise the sensilla in different genera and provide a system of sensilla designation for Neuroptera larvae. This study is illustrated with 36 morphological drawings.
The riffle beetle genus Hedyselmis Hinton, 1976 includes two species from the Malay Peninsula, with adults with a highly deviating morphology. Its phylogenetic relationships are unclear, although it has been hypothesized to be related to Graphelmis Delève, 1968, a large genus widely distributed in the Oriental and East Palaearctic regions. In this paper the larva of H. opis Hinton, 1976 is described based on material collected in the Cameron Highlands (Malaysia) and the conspecificity with co-existing adults tested using sequences of one nuclear (5' end of 18S rRNA) and three mitochondrial gene fragments (5' end of the large ribosomal unit + tRNAleu + 5' end of the NADH dehydrogenase subunit 1; 5' end of cytochrome c oxidase subunit I; and a fragment of cytochrome b) with a total of ca. 2,600 bp. This is the first example of the use of molecular data to match different life stages within the family Elmidae. The larva of H. opis has a subcylindrical body typical of many other elmid genera; abdominal segments 1-7 with preserved pleura; and ninth segment with oval operculum. The last instar larvae have clearly visible prominent spiracles on mesothorax and abdominal segments 1-8. The phylogenetic position of Hedyselmis in relation to Graphelmis was investigated using molecular data for three species of Graphelmis plus a selection of other Elmidae genera. Hedyselmis opis is nested within Graphelmis, confirming their close relationship and suggesting that their status requires taxonomic revision.
Preferences of young caterpillars of three species of Pieris (P. rapae crucivora Boisduval, P. melete Ménétriès, and P. napi japonica Shirôzu) (Lepidoptera: Pieridae) for the upper and lower surfaces of the leaves of their host plants (Brassicaceae) were investigated in the laboratory. On horseradish Armoracia rusticana Gaertn. Mey. et Scherb., which was provided as a common food for three species, second and third instar larvae of the respective species preferred the lower to the upper surface of horizontally placed leaves, irrespective of whether they hatched on the upper or lower surface. First instar larvae seemed to remain on the surface on which they hatched. However, first instar larvae of P. melete on Rorippa indica (L.), a natural food of P. melete in the field, and first instar larvae of P. napi japonica on Arabis flagellosa Miq., a natural food of P. napi japonica, preferred the lower to the upper surface, just as second and third instar larvae did. To elucidate the effects of leaf-surface preference, the percentage parasitism of P. rapae crucivora on Arm. rusticana and Ara. flagellosa by the parasitoid Cotesia glomerata (L.) (Hymenoptera: Braconidae) was investigated. On Arm. rusticana, the percentage parasitism of the larvae on the upper surface was higher than that of larvae on the lower surface. On Ara. flagellosa, however, percentages parasitism were nearly equal on both surfaces. Leaf-surface preference by the larvae of Pieris is discussed in terms of avoidance of parasitism by the parasitoid C. glomerata.