Sexual dimorphism in malpighian tubules of Pteronarcys californica Newport (Plecoptera)

The Malpighian tubules in female nymphs and adults of Pteronarcys californica Newport are larger and whiter than in males. This difference is detectable in nymphs as small as 300 mg in live weight (final instar nymphs weigh 800 to 1600 mg depending on sex), and is most pronounced in late nymphs and adults. These differences are thought to be related to the increased excretory load imposed by the synthesis of ooplasm in the late female nymph and adult.         

LV.—A new trilobite,Acidaspis (Pseudomonaspis) magnospina,from the Coniston limestone

Summary

The morphology of adults and young of Acanthomia tomentosicollis Stål. and A. horrida, Germ. is described. Measurements of head-width and antennal segments of nymphs and adults were made. The heads of adults and nymphs of A. tomentosicollis are wider than those of A. horrida. The comparisons of head and antennal growth showed that the two species developed at about the same rate. Some of the morphological features of these species are remarkably primitive and are probably new features known in the Pentatomamorpha.     

Bionomics of the cone spittlebug, Aphrophora canadensis (Homoptera: Cercopidae) on mugo pine in Idaho

The spittlebug, Aphrophora canadensis Walley (Homoptera: Cercopidae), was discovered at Moscow, Idaho, in 1979 infesting Pinus mugo Turra, an exotic ornamental pine. Masses of spittle, densely populated with nymphs, have continued to be abundant since then. The nymphs congregated and fed mainly on cones and did not cause visible reddening of foliage that is typical of other pine-infesting spittlebugs. Immature stages and behavior are described for the first time and are compared to other nearctic pine-infesting species. Beginning in mid-August, eggs were laid under fascicle sheaths at the bases of needles, where they overwintered. Nymphs appeared in late April and began transforming to adults in mid-July. Mating occurred from early August to late September. Adults lingered in diminishing numbers until mid-October.     

Drumming behavior and life history notes of a high-altitude Colorado population of the stonefly Isoperla petersoni Needham

Late instar nymphs and adults of a Colorado Hudsonian zone population of Isoperla petersoni Needham and Christenson were studied during the summer and early fall months of 1998, when stream temperature ranged from 3.3° C to 8.9° C. Early and middle instar nymphs were absent from July to October, and nymphs attained maximum size in mid-August during the 2nd week of adult field presence, suggesting a univoltine-slow life cycle. Nymphs were carnivorous and fed primarily on chironomid larvae. Adults were present from August to mid-October, with peak numbers of adult males and females occurring in mid-September and late September, respectively. Fecundity of field-collected females averaged 94.1 ± 45.15 eggs per female in September ( N = 81) and decreased to 85.2 ± 57.6 in October ( N = 12). Drumming duets were 2-way (male-female), and female answers followed male calls (nonoverlapped) or began before completion of the male call (overlapped). Male calls averaged 11.1 ± 2.09 beats and female answers averaged 6.2 ± 2.99, with mean intervals of 118 and 58 ms, respectively. The average number of female answer beats increased from 5.3 ± 2.56 when duets were nonoverlapped, to 6.6 ± 3.08 when overlapped.     

Aspects of the biology of the Melanesian stick-insect Eurycantha calcarata Lucas (Cheleutoptera: Phasmatidae)

A preliminary account of biological observations on Eurycantha calcarata Lucas is given, based on three years' laboratory data. The development of eggs, nymphs and adults was studied at room temperature (25 ± 1°C) and at 68–72% R.H.     

Substrate color matching in the grasshopper, Circotettix rabula (Orthoptera: Acrididae)

Mechanisms important in maintaining substrate color matching in the grasshopper, Circotettix rabula, were studied near Aspen, Colorado, during the summers of 1968 – 70. Studies concentrated on populations on gray shale and red sandstone substrates. In both areas, collections revealed appreciable numbers of mismatched phenotypes among all age groups. The possibility of developmental homochromy was examined by observation of nymphs held in rearing boxes on matching and contrasting soil colors. The behavioral selection of matching substrate colors was tested by preference experiments. While not negating the possibility of these mechanisms, results suggested that they were of minor importance. Predation experiments, using Sceloporus lizards, demonstrated significant levels of selective predation on mismatched nymphs on both red and gray substrates. Experiments with bird and mammal predators, using adult grasshoppers, gave similar results. Release - recapture experiments with marked adults in areas of red and gray substrates showed markedly higher disappearance rates for mismatched animals. These results are interpreted to indicate that selective predation on mismatched animals is a major factor in maintaining substrate color matching in this species.     

Immature stages of Chinavia musiva (Berg, 1878): a unique pattern in the morphology of Chinavia Orian, 1965 (Hemiptera,Pentatomidae)1

Specimens of Chinavia musiva were collected in Parque Estadual do Espinilho (Barra do Quaraí County, RS, Brazil). Insects were reared under controlled conditions (24±1°C; RH 70±10%; 12h L:12h D), and fed on green beans (Phaseolus vulgaris L.). Eggs of C. musiva differ from the pattern observed in other species of the genus due to chorion colour and surface, and aero‐micropylar processes, number and shape. Exclusive features of the species in the nymphal stage are head and thorax dull; variegated pattern of abdomen, and openings of the scent glands in conspicuous tubercles. Developmental time was, on average, 52 days; females laid more frequently egg masses with 14 or 42 eggs. Females collected from the field as nymphs exhibited higher reproductive performance than females reared on green beans as nymphs and adults, suggesting that wild hosts could be essential for the species life cycle.     

The stoneflies (Plecoptera) of Louisiana

A list of species, illustrated keys to nymphs and adults, distribution, and biological notes are presented for 24 stonefly species occurring in Louisiana. Leuctra moha?, Pteronarcys dorsata, Helopicus subvarians, Paragnetina kansensis, Paragnetina immarginata, Phasganophora capitata, and Acroneuria evoluta are recorded only from the florida parishes east of the Mississippi River. Isoperla Coushatta, Isoperla mohri, Neoperla clymene, an undescribed Neoperla (Sp. A), Paragnetina fumosa, Acroneuria abnormis, Acroneuria arenosa, Perlinella drymo, and Perlesta placida are found both east and west of the Mississippi; and Allocapnia granulata, Allocapnia malverna, Amphinemoura nigritta, and three species of Taeniopteryx have been recorded only west of the Mississippi. Habitats are primarily sand-bottomed streams of pine-hardwood rolling hills, constituting a portion of the western Gulf Coastal Plain. Few stoneflies occur in streams of the Mississippi Alluvial Plain, the Alluvial Atchafalaya Basin, or the lowlands along the Red River.     

Feeding interrelations of native fishes in a Sonoran Desert stream

Native fishes in Aravaipa Creek, Arizona, cropped foods proportional to abundance of those foods within the system. Ephemeropteran nymphs and adults comprised the major prey of 5 of 7 fishes ( Gila robusta, Meda fulgida, Rhinichthys osculus, Tiaroga cobitis, and Catostomus insignis ). The omnivorous Agosia chrysogaster ate almost as many nymphal mayflies as did the carnivores. Pantosteus clarki was herbivorous, taking animals only when they were abundant. When ephemeropterans decreased in abundance, a shift by some fish species occurred to other locally or seasonally abundant items. Other fishes continued to feed upon the same foods throughout the year. Abundance of invertebrates in Aravaipa Creek, coupled with marked spatial partitioning of habitat by fishes present, seemingly precluded severe interspecific interactions for food.     

A new species of Halolaelapidae (Acari: Mesostigmata: Rhodacaroidea) from beach wrack in Yaquina Bay,Oregon, USA,with comments on opisthonotal plasticity and cribral development in the family

Decomposing beach wrack in a backwater of Yaquina Bay, Oregon, was found to contain nymphs and adults of a previously undescribed species of the mite genus Halolaelaps (Halolaelapidae). Significant variation was noted among available specimens in the number of opisthonotal shield setae, a feature that has long been considered to be of critical importance in identifying celticus group species. The presence of a well-formed posterodorsal cribrum in this and related celticus group species prompted an examination of cribral development in the Halolaelapidae as a whole and revealed that posterodorsal cribral elements occur in various configurations in three of the four presently recognized halolaelapid genera. A narrow, transversely oriented configuration appears to be unique to members of the celticus species group.     

Systematic status of Hydrozetes octosetosus Willmann, 1932 (Acari: Oribatida: Hydrozetidae) in the light of ontogenetic and ecological studies

The systematic status of Hydrozetes octosetosus was investigated by comparing this species to H. lacustris, which is the type species for the genus Hydrozetes Berlese, 1902. These species are similar, but probably not synonyms as recently proposed. They differ mainly by the position of notogastral seta lm in the adult and position and length of this seta and total number of long setae in the posterior part of nymphs. In the adult of H. octosetosus, this seta inserts behind the opisthosomal gland opening (gla), but in front of it in H. lacustris. In the nymphs of H. octosetosus seta lm inserts behind gla opening, but medially to it in H. lacustris. In H. octosetosus this seta is very long and the total number of long setae in nymphs is four pairs, while in H. lacustris seta lm is short and the total number of long setae in nymphs is three pairs.     

Life history and ecology of Megarcys signata (Plecoptera: Perlodidae), Mill Creek, Wasatch Mountains, Utah

During an investigation of some of the stoneflies (Plecoptera) of Mill Creek, Wasatch Mountains, Utah, Megarcys signata, a large omnivorous stonefly, was found to have a univoltine life history and a slow seasonal life cycle. Temperature appears to affect the growth rate of Megarcys signata. Warmer stream temperatures accompany the acceleration of the growth rate, whereas cooler stream temperatures apparently retard the growth rate. Periods of maximum absolute growth rate correspond with maximum carnivorous feeding from August to September and March to April. Chironomidae, Ephemeroptera, and Plecoptera, in that order, were the most abundant prey in the foreguts. Young nymphs ingested considerable amounts of diatoms, filamentous algae, and detritus but not as much animal matter as did older nymphs. Megarcys signata was uniformly distributed throughout Mill Creek, except at the lowest station, where few nymphs were found. Emergence occurred in May and June, the peak occurring in June. The mean size of females and males decreased as emergence progressed.       

Mites coexistent with neotropical hispine beetles in unfurled leaves of Heliconia: a new genus and family of the Ascoidea (Acari: Mesostigmata: Gamasina)

The genus Antennocheles gen. nov. is based on adults and nymphs of two newly described species associated with hispine beetles of the genera Chelobasis and Cephaloleia occupying unfurled leaves of Heliconia in lowland rainforest of Costa Rica. Within the superfamily Ascoidea, this taxon is so distinctive morphologically and behaviourally as to justify its own family, Antennochelidae, fam. nov. These mites bear remarkably elongated cheliceral shafts, which may extend for lengths greater than the body but are fully ensheathed in repose within the body. Other unique attributes include linear arrangement of hypostomatic setae, a pore-like structure beside the corniculus, and adults with a pair of unique sternal invaginations for enlarged muscle insertions. While undergoing their life history in water films of unfurled host leaves, the mites exhibit a slow, swimming-like behaviour in quest for prey. As leaves unfurl, adult mites run quickly off and on their hispine beetle phoronts for dispersal.

http://zoobank.org/urn:lsid:zoobank.org:pub:0876014C-1433-463B-B1A4-4CD6886F9D28     

Morphology of abdominal evaporatoria in larvae of some Lygaeoidea (Insecta: Hemiptera: Heteroptera): function and bearing on classification

The dorsal abdominal scent glands of nymphs in Lygaeoidea are diverse. Some related characters, such as number and distribution of dorsal abdominal scent gland openings (DSOs), and shapes of dark plates surrounding DSOs have been commonly used in taxonomic and/or phylogenetic studies of Lygaeoidea. However, comparative studies of the cuticular fine structures surrounding the DSOs in lygaeoid (and other Heteroptera) nymphs are few. We examined the cuticular fine structures surrounding DSOs of fifth‐instar nymphs of 25 species in seven families of Lygaeoidea with scanning electron microscopy. The results showed that the structures surrounding DSOs, such as distribution pattern of cell network, type of network, type of non‐latticed area, pattern of channels for glandular secretion, are complicated and diverse at the family level, indicating that they are valuable in taxonomic and phylogenetic analyses.     

Distribution of shore bugs and shore flies at Sylvan Springs, Yellowstone National Park

Three species of shore bugs (Hemiptera: Saldidae) and 10 species of brine flies (Diptera: Ephydridae) were collected at Sylvan Springs (Wyoming section of Yellowstone National Park, USA), an area containing both acid and alkaline thermal springs. The fauna consists of both widespread (e.g., shore bugs Saldula comatula Parshley and Saldula explanata [Uhler] and shore flies Atissa litoralis [Cole] and Scatella stagnalis [Fallén]) and Yellowstone Park–endemic species (e.g., Saldula nr. arenicola and the shore fly Ephydra thermophila Cresson). The ratio of adults to nymphs of the numerically dominant shore bug Saldula nr. arenicola is higher along heated margins (11–12:1) than along near-ambient-temperature margins (0.6–2:1) of a thermal channel at Sylvan Springs; this may reflect differences in food availability, osmoregularity, thermal tolerance, predation, or other factors. Shore flies include species typical of acid ( E. thermophila ) and alkaline ( Paracoenia bisetosa [Coquillett] and Paracoenia turbida [Curran]) springs.     

A note on the food of Callibaetis (Ephemeroptera: Baetidae)

Callibaetis nymphs in Rattlesnake Springs, Hanford Reservation, Washington, feed almost exclusively on fine particulate organic matter (FPOM) collected from the stream bottom.     

Note on the occurrence of Siphlonurus autumnalis (Ephemeroptera: Siphlonuridae) in a Montana spring brook

The little-known mayfly Siphlonurus autumnalis McDunnough (Ephemeroptera: Siphlonuridae) was collected from several locations in its floodplain habitats along the Middle Fork of the Flathead River in western Montana. To confirm identification, nymphs were reared along with an associated species, S. occidentalis Eaton (Ephemeroptera: Siphlonuridae). Adults emerged from 6 September until 16 October. Habitats are described and the first photos of the 2 sexes are provided.     

Note on mortality of the emerging stonefly Pteronarcys californica on the Jocko River, Montana, USA

Cold air temperatures may have killed several emerging nymphs and adult Pteronarcys californica on the Jocko River, Montana. Some aquatic insect taxa emerge early on the Jocko River, likely due to warm water temperatures in winter and spring. At this location, P. californica emerges approximately 5–7 weeks earlier than it does on many other streams or rivers across the United States. We hypothesize that this earlier emergence may be a mortality factor when cold fronts cause air temperatures to drop below freezing. Other mortality factors are also discussed.