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.     

The occurrence of an additional instar in the development of Chorthippus brunneus (Orthoptera: Gomphocerinae)

In two populations of Chorthippus brunneus in the Breckland district of East Anglia an additional instar is interposed between instars II and III during the development of female nymphs. The IIa nymph occurs with a frequency approaching 100%, in both heavily and very lightly grazed grasslands.

The IIa nymph is intermediate in morphological characteristics between the second and third instars. It is characterized by having wing buds similar to those of a second instar except with more extensive venation, while the genitalia are more like those of a third-instar nymph. The pronotum length: head length ratio is approximately 1·0 and there are 16 or more annuli in the antennae.

Members of the population taken from the very lightly grazed grassland and raised in the laboratory on grass that had been heavily grazed by rabbits omitted the IIa instar and so passed through only four stadia during their development. In contrast, members of the population taken from the heavily grazed field site continued to include the IIa instar in their development when fed in the laboratory on grazed grass.

Comparisons with other studies of this species show that there is geographical variation with respect to numbers of instars passed through during development. The additional instar has been found only in East Anglia where the warmer sunnier climate, which is semi-continental in the Breckland district, leads to earlier hatching. This allows more time for an extra instar to be included in the development.

The ecological implications of the observed variation in life history are discussed.     

Description of the immature stages of Sigara (Tropocorixa) santiagiensis (Hungerford, 1928) (Insecta: Heteroptera: Corixidae)

The immature stages of Sigara santiagiensis are described and illustrated for the first time. The eggs of Sigara can be distinguished by the chorionic surface. The main characters separating the five nymphal instars of S. santiagiensis are: body and head lengths; body, head and eye widths; ocular index; numbers of transverse sulcations of the rostrum, setae on the inner surface of protibiotarsus, campaniform sensilla on posterior surface of protrochanter, spines on posteroventral surface of mesotibia and on tibial comb of metaleg, long, slender setae on posterodorsal surface of mesotarsus, spines and swimming hairs on anteroventral and posterodorsal surfaces of metatarsus; and grade of development of the wing pads. The body length, the chaetotaxy of the mesonotum, profemora and metafemora, protibiotarsus, metatibia, metatarsus and urosternites distinguish species or group of species of instars I and V of some of the species of the genus Sigara described up to now.     

Mating behaviour,nympho-imaginal development and description of a new Mesabolivar species (Araneae: Pholcidae) from the Brazilian dry forest

A new species of Mesabolivar is described from Brazilian forests: Mesabolivar delclaroi. The mating behaviour, postembryonic development, number of egg sacs and eggs, birth rate, number of instars, developmental time until adulthood, sex ratio and size of cephalothorax (per instar) were recorded. The sexual behaviour was described and categorized into four steps: courtship, pre-copulation, copulation and post-copulation. After hatching, individuals presented five instars until maturity. The mean number of eggs (42 ± 16.6) and live births (31.5 ± 3.4) of the first egg sac were significantly greater than that of a second one (23.8 ± 3.8, and 19.25 ± 3.9, respectively). The developmental time from birth to adulthood (130.8 ± 9.6 days) did not differ significantly between egg sacs produced (128.61 ± 11.1). The size of the cephalothorax did not differ among adults or between sexes. The sex ratio revealed a shift in favour of females (4: 3).     

Immature stages of Parrhasius polibetes (Lepidoptera: Lycaenidae): host plants,tending ants,natural enemies and morphology

Natural history and immature stage morphology of the facultative myrmecophilous butterfly Parrhasius polibetes (Stoll) (Lepidoptera: Lycaenidae) are described and illustrated through both light and scanning electron microscopy. Larvae underwent four instars. At the third instar, the dorsal nectar organ became present and functional, and larvae were facultatively tended by several ant species, those also tending plants bearing extrafloral nectaries and honeydew-producing hemipterans. Larvae were florivorous and polyphagous at the species level, using at least 44 species of plants in 19 families. Most host plants (～ 89%) had some type of ant-attractive features, such as extrafloral nectaries or ant-tended treehoppers. The host range of this butterfly species allows the use of floral resources throughout the year. Food sources that promote ant visitation, flower bud morphology and phenology appear to be related to the evolution and maintenance of polyphagy in this butterfly species.     

Larval growth rates and sexual differences of resource allocation in the cetoniine scarab Mecynorhina polyphemus Fabricius 1781 (Coleoptera: Scarabaeidae: Goliathini)

Larval ontogeny of the scarab Mecynorhina polyphemus was monitored throughout all instars, and larvae were weighed at 7-day intervals. Durations of the prepupal, pupal and postpupal stages were recorded. Larvae increase their body masses over 300 times during ontogeny. Male imagines are larger than females, and this is primarily a function of faster growth rates during instar III, resulting in significantly heavier larvae at the end of this instar. The durations of the three instars are not significantly different in males and females, but the duration of the prepupal and postpupal phases is significantly longer in males. There is a strong correlation in both sexes between maximal larval mass and the mass of the imago, but larval mass–imago mass scales with significantly different slopes in males and females. Male larvae must allocate increasingly more resources into production of cephalic horns with increments in larval mass, requiring differently proportioned pupal chambers.     

Cave Sinella (Collembola: Entomobryidae) from China

All nine Chinese cave Sinella species are reviewed; four of them from South China are new to science: Sinella lipsae sp. nov., Sinella longiantenna sp. nov., Sinella yunnanica sp. nov. and Sinella longiungula sp. nov. Some important characters, such as length of antennae, mucro, claw structure, chaetae on ventral side of the head and body chaetotaxy are discussed.     

Observations on the developmental biology of Cicindela arenicola Rumpp (Coleoptera: Cicindelidae)

Cicindela arenicola Rumpp is being considered for threatened and endangered status by the U.S. Fish and Wildlife Service. Little is known about the developmental biology of this species. Adults of C. arenicola were active from April through late June and late August through early November, but generally they were not on the surface when temperatures were below 19 C or above 45 C, or when conditions were windy, cloudy, or rainy. Mating and egg-laying occurred only during the spring. Five size classes (1-,2-,3-,4-, and 5-mm diameters) of larval burrow openings were observed. Burrows of 5 mm had a mean depth of 42.23 ± 8.81 cm (1 S.D.). Larvae of C. arenicola were active from April through June and late September through mid-November. Developmental times and larval size were affected by food supplementation. Nearly all food-supplemented, 1-mm, first instars molted to larger second instars of3-mm diameter. Most nonsupplemented larvae spent several months as 2-mm second instars before growing to 3 mm in diameter. Food-supplemented larvae reached the third instar in approximately 13 months, while nonsupplemented larvae took slightly over two years to reach this stage. Development from egg to adult was estimated at two years for food-supplemented larvae and three and one-half to four years for nonsupplemented larvae. Cattle had a significant effect on larval mortality. A high percentage (76-80%) of larval C. arenicola that were stepped on by cattle never reopened their burrows. Only 14% of undisturbed larvae never reopened their burrows. Approximately 15% of 150 larvae marked in 1988 reopened burrows in 1989.     

Some observations on the chaetotaxy of the legs of larval Ixodidae (Acari: Metastigmata)

Summary

The segmental chaetotaxy of the legs of some larval ixodid ticks has been studied, employing the system of nomenclature currently used for the mesostigmatic mites. Preliminary results indicate that in common with the larval Mesostigmata, the family Ixodidae has a relatively constant larval leg chaetotaxy which allows the subfamilies and tribes to be distinguished on the basis of the chaetotaxy of the tibiae.     

The tortoise caterpillar: carnivory and armoured larval morphology of the metalmark butterfly Pachythone xanthe (Lepidoptera: Riodinidae)

ABSTRACT

The natural history and morphology of the later instars and pupa of the metalmark butterfly Pachythone xanthe H. Bates are described and illustrated for the first time. The caterpillars are myrmecophilous and carnivorous, feeding on scale insects (Hemiptera: Coccoidea) tended by Azteca cf. chartifex Forel (Formicidae: Dolichoderinae) ants and appear to be physically shielded from potential ant attacks by a carapace-like body that protects the head and appendages. In addition, the larvae present several types of specialised setae and ant-organs such as perforated cupola organs, glandular openings and functional tentacle nectary organs that may be related to appeasement of aggressive ant behaviour. Our results reveal the first detailed life cycle data for the Pachythonina subtribe and record a new independent origin of carnivory in Riodinidae.     

The status of Hemilecanium imbricans (Green) (Homoptera : Coccoidea) in Africa south of the Sahara

Summary

This paper describes the findings from two series of observations on variation in C. austropalpalis L. and R. In Series I the distribution of head capsule lengths of 174 larvae, collected from 11 breeding sites in S.E. Queensland, was polymodal. Polymodality was also shown by the wing lengths of 15♂, 27♀ reared from 7 of the sites. In Series II the head lengths of 302 larvae from 5 sites (one not in Series I) gave the same polymodality, interpreted as representing 3rd and 4th instars of two forms A (smaller) and B (larger). 276 of these larvae, grouped on head length, were reared on agar and small nematodes, producing 62♂, 70♀ C. austropalpalis and 13♂, 5♀ C. narrabeenensis. The latter was not the cause of the polymodality. Adult wing lengths were bimodal in each sex. Form B was longer winged than form A. Within each form there was no significant correlation between larval head length and adult wing length. Only one of the many additional characters (19 in ♀; 22 in ♂) examined, differed between the two forms. Form B had more distinctly patterned wings with the intercalary pale spot more obvious. The results are discussed.     

Growth ‘rules’ and the larvae of decapod crustaceans

Summary

Statements that have attempted to express the relationship between the sizes of successive arthropodan instars are examined with reference to published data on larval decapod crustaceans.

The conclusions reached are (a) that ‘Brooks's Law’, which simply states that the lengths of successive instars form an exponential series, generally holds good in decapod larvae, (b) that ‘Przibram's Rule’, stating that the weight increase between instars is always by some power of 2, is not supported by the observed length changes, and (c) that Gurney's suggestion that growth factors in decapod larvae do not normally exceed about 1·5 is not applicable to the order as a whole, but may be valid for some sub-groups within it.     

The early larval instars of Lucilia sericata and Lucilia cuprina (Diptera,Calliphoridae): myiasis blowflies of Africa and Australia

Lucilia cuprina and Lucilia sericata are probably the two most important sheep myiasis flies in the southern hemisphere. This paper describes and illustrates structural features that enable reliable specific identification of the first and second instars of these species of be made.     

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.     

Biology and immature stages of Panteles schnetzeanus (Hymenoptera: Ichneumonidae), a parasitoid of Lampronia fuscatella (Lepidoptera: Incurvariidae)

Panteles schnetzeanus (Roman), a parasitoid of the gall‐forming incurvariid moth Lampronia fuscatella (Tengström) and currently placed in the Stilbopinae, is shown to be a solitary koinobiont larval endoparasitoid. The large dark‐pigmented eggs possess a hook‐like tail which is embedded in host tissue, typically at the posterior or anterior end of the host. In cases of superparasitism, which represented 70% of cases, only a single egg hatches. The first instar, prepupa and final larval instar head capsules are described and illustrated. Many differences between the biology of Panteles and of Stilbops are discussed. Circumstantial evidence that suggests that Panteles may have an alternative host is also presented based on the emergence dates for it and the Lampronia together with the size, number and placement of the Panteles eggs. DNA sequence data additionally provide the first record of a eupelmid as attacking a gall‐forming incurvariid/parasitoid system, though it is not clear whether this was an hyperparasitoid on the Panteles or a primary on the incurvariid.