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.     

Development and longevity of ephemeral and perennial leaves on Artemisia tridentata Nutt. ssp. wyomingensis

Big sagebrush ( Artemisia tridentata Nutt.) is one of the most successful plants in the Great Basin based on its abundance and wide distribution. The development of dimorphic leaves may be an important mechanism attributing to its adaptive and competitive abilities. Development, persistence, and proportions of ephemeral and perennial leaves on Wyoming big sagebrush ( Artemisia tridentata Nutt. ssp. wyomingensis ) were studied for two years. The large ephemeral leaves are the first to develop in early spring. As early developing ephemerals mature and stems elongate, new ephemeral and perennial leaves develop in the axes of these large ephemerals. Perennial leaves expanded in the summer of their first growing season, persisting on the shrub until their abscission during summer drought of the second growing season. Plants maintained 33% of their leaf weight through the winters of 1985 and 1986. Active leaf and stem growth occurred at soil water potentials above –0.2 MPa.     

A new species of Josephiella (Hymenoptera: Agaonidae) forming leaf galls on Ficus microcarpa L. (Moraceae)

A second species of Josephiella Narendran, J. microcarpae, is described and figured, based on specimens reared in Hawaii, California and the Canary Islands. This wasp develops in galls on the leaves of Ficus microcarpa L., a widely cultivated ornamental banyan tree that is native to South-East Asia and adjacent islands. It has not been found on any other hosts. Both sexes are described, and males, which are apparently all fully winged, are relatively rare. We postulate that this wasp is a recent introduction into Hawaii, California and the Canary Islands, from an unknown location in South-East Asia, where Ficus microcarpa is native.     

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.     

Nesting habits of the Japanese foliage spider,Cheiracanthium japonicum (Araneae: Miturgidae): host plant preference based on the physical traits of plant leaves

A Japanese foliage spider, Cheiracanthium japonicum, builds nests with plant leaves. The nests are classified into seven types in relation to the seasons and purposes of nesting. We investigated whether the spider selects a plant species according to the nest type and how the physical traits of leaves influence the spider's plant selection. The difference between the composition of the host plant species used for nesting and that of the seasonal vegetation cover was confirmed. This suggests that the spider chooses the host plant species regardless of its abundance in their habitat. Early juveniles use small living or large dead leaves of various plant species to build moulting nests. Females prefer long and large leaves found in Miscanthus sinensis and Phragmites japonica over other plant leaves to build breeding nests.     

Mining patterns of the aspen leaf miner, Phyllocnistis populiella, on its host plant, Populus tremuloides

Feeding behavior of aspen leaf miner ( Phyllocnistis populiella ) larvae on quaking aspen ( Populus tremuloides ) leaves was examined, by using image-analysis software, to determine the pattern and distance of the larvae’s mining trails and measure the surface area of infested leaves and consumed leaf tissue. Mining pathways between hatching and pupation sites were serpentine and generally followed predictable, sequential changes in orientation. This pattern was most obvious in smaller leaves, those with a surface area of about 700 mm 2 or less. In leaves larger than 700 mm 2 , plasticity in mining behavior increased. The serpentine pattern was initiated but became truncated when larvae reached full growth without having to consume all available leaf material. The final phase of the behavioral program was still executed, however, and larvae entered pupation at the usual leaf-edge location. We hypothesize that the serpentine pattern is genetically controlled and that it has been selected for because it promotes efficient consumption of a fixed food supply and ensures a favorable location for pupation, especially when reproductive females oviposit on small leaves. Se examinó el comportamiento alimenticio de la larva del minero de hoja de álamo ( Phyllocnistis populiella ) en las hojas del álamo temblante ( Populus tremuloides ) utilizando software de análisis de imágenes para determinar el patrón y la longitud del rastro de las larvas y medir la superficie de las hojas infestadas y del tejido de hoja consumido. Los rastros del minero entre los sitios de eclosión y los de pupación fueron serpentinos, y en general sus cambios de orientación fueron predecibles y secuenciales. Esto fue más obvio en las hojas pequeñas, aquellas con una superficie de menos de 700 mm 2 . En las hojas con una superficie mayor de 700 mm 2 aumentó la plasticidad en el comportamiento minero. El patrón serpentino apareció al inicio pero se truncó cuando las larvas alcanzaron su pleno desarrollo sin tener que consumir todo el material herbáceo disponible. Sin embargo, la última fase del patrón conductual aún se llevó a cabo, y comenzaron la pupación en el borde de la hoja como de costumbre. Planteamos la hipótesis de que el patrón serpentino tiene origen genético y que ha sido seleccionado a favor porque facilita el consumo eficiente de un suministro fijo de alimento y garantiza un lugar favorable para la pupación, especialmente cuando las hembras reproductoras ovipositan en hojas pequeñas.     

Tent construction and social organization in Cynopterus brachyotis (Muller) (Chiroptera: Pteropodidae) in Peninsular Malaysia

This study examined the tent-making behaviour and social organization of the lesser dog-faced fruit bat, Cynopterus brachyotis (Muller), in Peninsular Malaysia. Cynopterus brachyotis alters the leaves of eight species of broad-leafed palms (Palmae) to form palmate umbrella tents, the leaves of Scindapsus aureus Engl. (Araceae) to form apical tents, and the leaves of Dracaena fragrans Ker-Gawl (Liliaceae) to form conical tents. Cynopterus brachyotis also severed the roots of Cymbidium finlaysonianum Lindl (Orchidaceae), and the leaves and stems of Philodendron lacerum Schott (Araceae) to form stem tents. In addition, C. brachyotis also roosted in unmodified plants. Cynopterus brachyotis possesses a harem type of social organization, but it was not possible to distinguish between a resource-defence polygyny and female-defence polygyny mating system. Our observations indicate that dominant males construct tents, and recruit females for the purpose of gaining reproductive access.     

Natural history of the lizard Enyalius perditus (Squamata: Leiosauridae) from an Atlantic forest remnant in southeastern Brazil

The natural history of the lizard Enyalius perditus was studied from August 2005 to July 2006, at Parque Estadual Nova Baden, in the municipality of Lambari, State of Minas Gerais, south-eastern Brazil. We found that E. perditus may be considered a semi-arboreal species, like other species in the genus, sleeping on vegetation (slim branches or large leaves) at night, possibly to minimize predation. Females with enlarged follicles or oviducal eggs were found from November to January and juveniles recruited at the end of the dry season and beginning of the rainy season, in October. The diet of this lizard is composed mainly of Lepidoptera larvae, Araneae and Formicidae. Females were larger than males, and juvenile coloration is similar to that of adult females.     

Rhodanese activity in Lotus corniculatus s.l.

Rhodanese (EC 2.8.1.1) is a sulphurtransferase which catalyses in vitro the formation of thiocyanate from cyanide and thiosulphate or some other sulphur donor. One proposed function of this multifunctional enzyme in vivo is detoxification of cyanide.

Lotus corniculatus s.l. is genetically polymorphic for cyanogenesis. Here we present the first investigation of such a polymorphic species group for its rhodanese content.

Enzymatic thiocyanate formation was easily detected in the leaves of Lotus alpinus and L. corniculatus from various natural habitats in Switzerland. All samples taken from these two species were found to contain a higher level of rhodanese activity than samples from the leaves of the six cultivated higher plants examined. Most interestingly, the differences observed within the Lotus species appear to be correlated with the polymorphism of cyanogenesis: cyanogenic plants AcLi showed much higher rhodanese activities than the acyanogenic types Acli and acLi. This correlation suggests that rhodanese provides a mechanism to detoxify cyanide in cyanogenic plants.     

Natural history of Peucetia flava (Araneae,Oxyopidae): seasonal density fluctuation,phenology and sex ratio on the glandular plant Rhyncanthera dichotoma (Melastomataceae)

The seasonal density fluctuation, phenology and sex ratio of Peucetia flava (Oxyopidae) on Rhyncanthera dichotoma (Melastomataceae) were investigated during a year in a swamp in southeastern Brazil. Peucetia flava displayed an unusual non‐seasonal life cycle and the population size varied little over the year. The density of Peucetia spiders increased with the increase in abundance of leaves and number of arthropods adhered to glandular trichomes on R. dichotoma leaves. Our findings suggest that seasonal density fluctuation of Peucetia may be influenced by foraging site availability (i.e. leaves) and prey supply (i.e. arthropods adhering to glandular trichomes). The unusual seasonal stability of P. flava may be related to the type of habitat in which this spider occurs (swamp), because of the constant input of allochthonous resources from the water source, i.e. aquatic insects that migrate to the terrestrial environment.     

Ants feeding on anal exudate from tortricid larvae: a new type of trophobiosis

A new type of trophobiosis between tortricid larvae of a hitherto unknown genus and species, and various ant species of the subfamilies Formicinae, Dolichoderinae and Myrmicinae, was found in Malaysia. The larvae live in silken shelters fixed to the leaves of bamboo. In response to mechanical stimuli from the ants, they discharge from the anus a liquid containing sugar and amino acids and/or protein. The tortricid is described as Semutophila saccharopa gen. nov., sp. nov.; a second species, S. susurra sp. nov., is described from New Guinea.     

Maintenance of colour polymorphism in the leaf beetle Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae: Paropsini)

Intra-specific colour differences in insects may occur as a result of environmental factors such as food type, temperature and humidity, or may be under genetic control. These colour polymorphisms may result in fitness differences through several mechanisms, including mate selection, camouflage from or warning to natural enemies, and heat absorption. Two colour morphs of adult Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae: Paropsini) are present in the field in mainland Australia and Tasmania: a common green-brown form, and a rare black form. Tasmanian populations were sampled to assess the frequency of each morph at eight localities. The black form represented less than 3% of beetles (N=1724), with the proportion not significantly different between localities. Crossing tests using the two colour morphs of C. agricola showed that the black form was genetically dominant over the common form. To assess whether colour morphs had any fitness differences, we measured pre-oviposition period, fecundity, longevity, adult size and egg hatch rate, which each showed no significant difference between colour morphs. Field sampling of mating pairs and rearing the offspring of field-collected females showed no evidence of non-random mating. Modelling the population over 100 generations confirmed that for this species, melanism is controlled by a dominant but neutral allele, and, thus, is maintained at a constant low level in the population.     

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.     

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.     

Reproductive pattern in the southernmost populations of South American redbelly toads

Anurans can be classified as explosive or prolonged breeders. In species with short breeding periods, intensive competition for females is expected. We analyse the temporal breeding pattern of Melanophryniscus aff. montevidensis, a bufonid inhabiting grasslands of Argentina, whose breeding is concentrated in events of short duration. Males are active during more than one breeding event per season, whereas most females take part in a single event per season. Active males outnumbered females by up to 14 times at one event, operational sex ratio (OSR) ranged from 0.07 to 0.75 and intensity of sexual selection (I _s) from 0.69 to 24. We found a negative association between I _s and OSR, but no correlation between number of active males per event and OSR or I _s. The OSR is the key that regulates the intensity of sexual selection, nevertheless, and in spite of being explosive breeders, females would potentially have chances to select their mate.     

A new species of Sarcofahrtiopsis Hall (Diptera: Sarcophagidae) living in roosts of Spix's disk-winged bat Thyroptera tricolor Spix (Chiroptera) in Costa Rica

Sarcofahrtiopsis thyropteronthos sp. n. is described from Costa Rica. All specimens were bred from faeces taken from young, tubular leaves of musoid plants (genera Heliconia and Calathea) used as roosts by Spix's disk-winged bat Thyroptera tricolor Spix. Larvae were observed in practically all roosts suggesting a highly specialized association.