Intense inhabitation and relaxed host-leaf preference of aquatic chironomid leaf-miners in headwater streams in Asian lucidophyllous forests

Submerged leaf litter in headwater streams covered by Asian lucidophyllous (glossy broad-leaved evergreen) forests was found to be frequently processed by leaf-mining larvae of a chironomid, Stenochironomus okialbus. The larva gnaws plant tissue of the mine wall while swimming and undulating its body in the water-filled mine. To detect the level of the inhabitation and host-preference of the aquatic leaf-miner, extensive samplings of mined leaves were made in various headwater streams covered by lucidophyllous forests in the Japanese Island Arc. The chironomid showed significant preference for leaf texture (evergreen to deciduous leaves) and for specific taxonomic groups of the host plants (Fagaceae and Lauraceae), whereas diverse taxa of leaves were utilised. The relaxed host-leaf preference unique among herbivorous insects is suggested to be caused by the larval water-circulating behaviour in their porous mines and by leaching and microbial decomposition of plants’ secondary metabolites in submerged leaves.     

The biology of some Phyllonorycter species (Lepidoptera: Gracillariidae) mining leaves of oak and beech

Summary

The oak leaf miners P. quercifoliella and P. harrisella were encountered at first generation densities of 40 and 48 mines per 1000 leaves in 1968 and 1969 and second generation densities of 179 and 211 mines per 1000 leaves. The 1969 densities for the two generations of P. maestingella on beech were 54 and 118 mines per 1000 leaves. The mines on oak were found to be aggregated on certain trees but the reason for this was not discovered. There was also aggregation on certain leaves within a tree.

The moths had two generations of adults per year at Dunham, the first generation mines appearing on the leaves in June and the second generation mines in August. P. maestingella seemed to be slightly in advance of the oak species.

The sampling data provided estimates of the mortality through 1969. Larval interference and mine damage caused negligible mortality. Death due to unknown factors figured prominently in the early instars but in the later instars, especially during the second generation, parasitism was important. Leaf browning was an added source of mortality in the second generation as was overwintering.

Fifteen species of hymenopterous parasites were bred from Phyllonorycter on oak and eight from P. maestingella on beech. Among these were some new host records. T. ecus was the most common first generation parasite of oak mines and C. nephereus. E. latreillei, S. sericeicornis, C. diallus and C. vittatus figured prominently in the second generation parasite complex. E. cilla was the commonest parasite of both generations of P. maestingella.     

Influence of the holly leaf miner,Phytomyza ilicis (Diptera Agromyzidae), on leaf abscission

Holly trees were sampled at two heights for 11 annual generations of Phytomyza ilicis Curtis. The number of mines per 1000 leaves, mine intensity, was consistently more at the lower height. Mine-induced leaf abscission led to a reduction in mine intensity from 1- to 2-year-old leaves. Abscission was shown to have been greater in samples taken from higher in the tree. There was a suggestion of a density-dependent effect on the probability of mine-induced abscission.     

The armoured scale insects (Homoptera: Diaspididae) of avocado trees in Israel

Summary

Seven species of armoured scale insects infest avocado in Israel. Hemiberlesia lataniae (Signoret) and Abgrallaspis cyanophylli (Signoret) are the most abundant. Avocado seedlings become infested in the nurseries, thus serving as important sources for commercial grove contamination. Because larger diaspidid populations develop at the inside of the trees (as compared to their outside), and at height levels of 1·5–2·0 m (compared to 5·0–6·0 m), these regions were regularly sampled. Equal-area examinations of bark and leaf revealed that H. lataniae prefers the bark, A. cyanophylli the leaves. The populations of both scales undergo similar annual cycles on leaves, peaking during winter, ebbing in early summer. The specific settling pattern of most diaspidids on avocado leaves were figured. The somewhat-different settling sites of H. lataniae and A. cyanophylli apparently preclude competition when low numbers are present, but the former may be partially inhibited when large populations develop. Several predators and hymenopterous parasitoids attack the diaspidids, the parasitoids being most active in early summer. No economic injury to local avocado fruit by armoured scale insects has been reported in recent years. The reasons for this are discussed, and it is recommended that the present situation, in which no insecticides are used in avocado groves, be maintained.     

The preimaginal stages of Minotetrastichus frontalis (Nees) and Chrysocharis laomedon (Walker) (Hymenoptera: Eulophidae), parasitoids associated with Phyllonorycter issikii (Kumata) (Lepidoptera,Gracillariidae)

The biology and morphology of the early larval instars of Minotetrastichus frontalis (Nees) are redescribed and the morphology of the preimaginal stages of Chrysocharis laomedon (Walker) (Hymenoptera: Eulophidae) are described in detail for the first time. Both species are larval-pupal parasitoids of Phyllonorycter issikii (Lepidoptera, Gracillariidae), which is associated with Tilia sp. The female of M. frontalis lays her egg beside the host larva and the newly hatched first instar larva moves and has to find the host larva. The larva of P. issikii tries to continue its feeding but never pupates after paralysis. The female of C. laomedon lays its egg inside the cuticle of the larva of P. issikii, but the newly hatched parasitoid larva vacates the host larva and develops externally on its surface as an ectoparasitoid. Such behaviour might be facilitated by the constant temperature and humidity inside the mine. Some peculiarities of parasitoid–host relationships are described and discussed.     

Five invaginations and shedding of the larval epidermis during development of the hoplonemertean Pantinonemertes californiensis (Nemertea: Hoplonemertea)

We describe the planuliform larval development of the high intertidal hoplonemertean Pantinonemertes californiensis using confocal microscopy. We discovered that the newly hatched planuliform larva has two pairs of epidermal invaginations that disappear later in development. The anterior pair of invaginations has an apparent counterpart in other planuliform nemertean larvae; they give rise to the cerebral organs in at least two other hoplonemertean species. Although the adult P. californiensis possesses cerebral organs, we were not able to distinguish the anterior invaginations after 3 days of development. The developmental fate and homology of the posterior pair of invaginations is uncertain. We show that the proboscis develops in newly hatched larvae as a fifth distinct invagination just ventral of the apical plate. P. californiensis possesses a transitory larval epidermis, composed of approximately 80 multiciliated cells, which is normally shed at 3–4 days of development at 12–16°C.     

A new species of Melanagromyza (Diptera: Agromyzidae) mining leaves of Bromelia pinguin (Bromeliaceae) in a dry forest in Costa Rica

Melanagromyza rosales, sp. nov., from Costa Rica is described and its natural history is summarized. Larvae are miners in leaves of Bromelia pinguin, a large terrestrial rosette plant. They form conspicuous longitudinal mines that may be over 1 m long. Adult emergence is virtually simultaneous for all individuals, probably triggered by temperature cues. Populations are low for many generations with brief periods of abundance.     

Generalist hymenopteran parasitoids of the leaf-miner Chromatomyia fuscula (Zett.) (Dipt.: Agromyzidae)

In southeastern Norway, by the last week of June (1992), 48%of Chromatomyia fuscula emerged, based on the number of mines collected from Hordeum vulgare leaves. Among the parasitoids Diglyphus begini was the dominant species, but Cirrospilus vittatus and Neochrysocharis aratus also emerged in significant numbers. During June and July, N. aratus was the dominant species in the 1st and 2nd leaves, but D. begini was dominant in the 4th to 6th leaves. C. vittatus and Cyrtogaster vulgaris affected all larvae of the leaf-miner fly, living on various leaves. In central Norway, 48% of C. fuscula also emerged. C. vulgaris and D. begini were the dominant parasitoids and C. vittatus was also found. C. fuscula has no specialist parasitoids. Adults of the generalist parasitoids of the leafminers always search for different hosts. In investigation of the parasitoid complex of a lepidopteran leaf-miner, Phyllocnistis labyrinthella (living in Populus tremula leaves at the edge of the examined barley field), three shared parasitoids (C. vittatus, Pnigalio soemius and Pnigalio pectinicornis) were found. The complex network of host plant-phytophagous insect-insect parasitoid-facultative hyperparasitoid relationship is discussed.     

Contrasting modes of handling moss for feeding and case‐building by the caddisfly Scelotrichia willcairnsi (Insecta: Trichoptera)

Final‐instar larvae of the microcaddisfly, Scelotrichia willcairnsi sp. nov. (Trichoptera: Hydroptilidae) were discovered feeding on a moss, Platyhypnidium muelleri in north‐eastern Queensland. Not only do the larvae feed on the moss, but their cases are constructed from fragments of moss leaves. Microscopic examination of larval guts and cases showed a total contrast in the angle at which the moss leaves are cut for each purpose: for cases the moss leaves are cut longitudinally, in parallel with the length of the cells, whereas for feeding the leaves are cut perpendicular to the leaf margin, across the cells, presumably an adaptation that releases the cell contents for digestion. The new caddisfly species is described based on the adult males. Scelotrichia willcairnsi represents the first Australian record of the South‐east Asian‐New Guinean Stactobiini genus Scelotrichia.     

The morphology and biology of Pterodunga mirabile Daccordi,an unusual subsocial Chrysomeline (Coleoptera: Chrysomelidae)

New information is provided on the morphology and biology of the Australian leaf‐beetle Pterodunga mirabile Daccordi. This species is unusual in the Chrysomelinae for the following features: adult with deeply grooved prothoracic hypopleuron, laterally pointed elytral margins, concealed mesoventrite and fused abdominal ventrites; female ovoviviparous and without spermatheca; first‐instar larva with lappet‐like sclerites; maternal care; host plant in the Proteaceae. The systematic position and conservation status of Pterodunga are discussed. Maternal care in the Chrysomelinae and Proteaceae‐feeding in the Chrysomelidae are reviewed. The first record of maternal care in Chrysomelinae, for Labidomera suturella Guérin‐Méneville, is shown to be a misidentification of Platyphora selvae Daccordi.     

The identity of Orius tantillus (Motschulsky) and notes on other Oriental Anthocoridae (Hemiptera,Heteroptera)

Abstract

Studies on the biology of Toxoptera aurantii (Boy.) showed that populations of the aphid contain females only, and that reproduction is parthenogenetic and viviparous and occurs exclusively on the undersurface of flush leaves. The aphid is described and a key is drawn for the various instars. The development of the aphid is temperature-dependent but at the optimum temperature it takes 6 days to become adult. The incidence of alates in populations is influenced both by high aphid density and leaf age.     

Bionomics,behaviour and immature stages of Pelecotoma fennica (Paykull) (Coleoptera: Rhipiphoridae)

Ptilinus fuscus (Anobiidae) was confirmed as the host species of Pelecotoma fennica (Rhipiphoridae, Pelecotominae). Females of Pelecotoma oviposit into the wood infested by the host larvae. First-instar larvae are elongate, unsclerotized, very different from the triungulinid larvae known in other rhipiphorids. They search actively for the host larvae in the wood; no phoresy is involved in the life cycle. The first-instar larvae temporarily paralyse the host larva and enter its body, overwintering (some perhaps more than once) as an endoparasite. In the spring of the year of emergence, the endoparasite engorges enormously (without moulting) and develops a special sclerotized caudal structure which is then used for perforation of the host's integument. The larva undergoes a further four ectoparasitic instars. The fifth (i.e. fourth ectoparasitic) instar differs considerably from the preceding three, and is capable of boring through the wood to prepare the emergence gallery for the adult. Pupation occurs in the wood. The rate of parasitization may locally far exceed 50%. Superparasitization by the first-instar larvae is possible, but usually only 1 larva survives to the ectoparasitic stage. Larval morphology of Pelecotoma is described and illustrated. Additional data on bionomics and larval morphology are also presented for the genus Metoecus (Rhipiphorinae). Comparing the biology and larval morphology of Pelecotoma with other Rhipiphoridae, it is assumed that ancestral rhipiphorids may have been xylophilous Tenebrionoidea with predaceous or omnivorous larvae, and that the ‘triungulinid’ larvae and phoretic habits may not belong to the groundplan of the family Rhipiphoridae. The widespread opinion considering Rhipiphoridae closely related to the family Mordellidae is questioned.     

Morphology and chaetotaxy of the immature stages of the scorpionfly Panorpa liui Hua (Mecoptera: Panorpidae) with notes on its biology

The immature stages of the scorpionfly Panorpa liui Hua were obtained through rearing. The egg, larva and pupa were observed using light and scanning electron microscopy with special reference to the chaetotaxy of the first instar larva and pupa. The larva is of the eruciform type, with three pairs of thoracic legs and eight pairs of abdominal prolegs. The head of the larva bears a pair of compound eyes, each of which consists of 26 ommatidia. A fleshy tibial lobe is borne distally on the mesal side of the tibia of the thoracic legs. The telson bears a protrusile sucker of four anal forks. The pupa is exarate and decticous with sexual dimorphism in chaetotaxy and caudal segments. This species completes two generations per year, overwintering as the prepupal stage in the soil. The durations of egg, larva and pupa are 3–4, 13–19 and 8–10 days, respectively.     

On the parasitoid community of Aulacidea laurae (Hym., Cynipidae), with description of a new species of Adontomerus (Hym., Torymidae)

An account is given of parasitoids (Hym., Chalcidoidea) reared from Spanish galls of Aulacidea laurae (Hymenoptera, Cynipidae) which develop in achenes of Scorzonera laciniata (Asteraceae). The parasitoid community includes Adontomerus brevicaudatus (Hym., Torymidae) which is described as new. Final instar larva of the new species is also described. The generic placement of A. brevicaudatus and the composition of the parasitoid community are discussed.     

On Simulium xanthinum,a curious yellow-bodied blackfly of the southwestern Palaearctic region (Diptera: Simuliidae)

An account is given of Simulium xanthinum, an unfamiliar simuliid of the southwestern Palaearctic area remarkable for its mainly bright orange-yellow adult and for the clear yellow-green colour of its larva when alive. The species is described in all life stages (except the unknown egg), and the name Simulium gaudi confirmed as a new synonym of S. xanthinum after examination of types and other material. The finding is reported of pupae and larvae in several limestone streams of Andalusia (southern Spain), notably in the headwaters of the Rio Guadalquivir. SEM examination of the heavily sculptured surface of the pupal gill seems to reveal the occurrence of rows of micropores, and this finding is briefly discussed for its bearing on current debate about the nature of the simuliid pupal gill plastron.     

On the status of Arcitalitrus dorrieni (Crustacea: Amphipoda) on the island of Colonsay,Inner Hebrides

The presence of the landhopper Arcitalitrus dorrieni (Hunt) is reported on the island of Colonsay, Inner Hebrides. It is widely distributed there amongst deciduous leaf litter in forested areas but also occurs in bracken litter and scrub grassland. The species is an introduction from Australia, doubtless transported inadvertently among plants brought to the gardens at Colonsay House. It is, however, not restricted to the ornamental plantings but has colonized native woodland. Maximum population density recorded under leaf litter was 680 m². Amphipods avoid waterlogged or dry situations preferring to burrow in moist soil under litter from deciduous trees. Coniferous woodlands are more sparsely colonized. Rate of spread (minimum) from the original locus is calculated at c. 25 m/year. Arcitalitrus may prefer to eat sycamore leaves (cf. oak, beech). Ovigerous females are reported for May but no evidence exists for a release of young any earlier in the year. Immature amphipods seem to live more covert lives in the soil beneath the superficial litter layer. Eggs are relatively large and few in number. Amphipods may avoid ants but may have a mite living in phoretic or ectoparasitic association.     

The use of epiphylls as larval hostplants by the neotropical riodinid butterfly,Sarota gyas

The neotropical riodinid butterfly Sarota gyas is shown to utilize non-nitrogen fixing epiphylls as larval hostplants. The host substrate where the epiphylls grow appears unimportant to oviposition by adults or feeding by larvae. The larva of S. gyas is described and the use of long setae as a defense by amymecophilous riodinids is discussed.