An atlas of the developing Tribolium castaneum brain reveals conserved anatomy and divergent timing to Drosophila melanogaster

Insect brains are formed by conserved sets of neural lineages whose fibres form cohesive bundles with characteristic projection patterns. Within the brain neuropil these bundles establish a system of fascicles constituting the macrocircuitry of the brain. The overall architecture of the neuropils and the macrocircuitry appear to be conserved. However, variation is observed e.g., in size and shape and timing of development. Unfortunately, the developmental and genetic basis of this variation is poorly understood although the rise of new genetically tractable model organisms such as the red flour beetle Tribolium castaneum allows the possibility to gain mechanistic insights. To facilitate such work, we present an atlas of the developing brain of T. castaneum, covering the first larval instar, the prepupal stage and the adult, by combining wholemount immunohistochemical labelling of fibre bundles (acetylated tubulin) and neuropils (synapsin) with digital 3D reconstruction using the TrakEM2 software package. Upon comparing this anatomical dataset with the published work in D. melanogaster, we confirm an overall high degree of conservation. Fibre tracts and neuropil fascicles, which can be visualized by global neuronal antibodies like anti-acetylated tubulin in all invertebrate brains, create a rich anatomical framework to which individual neurons or other regions of interest can be referred to. The framework of a largely conserved pattern allowed us to describe differences between the two species with respect to parameters such as timing of neuron proliferation and maturation. These features likely reflect adaptive changes in developmental timing that govern the change from larval to adult brain.

Morphology of immature stages and life cycle of Monotoma testacea Motschulsky (Coleoptera: Monotomidae)

The egg, all three larval instars, and pupa are described for the cucujoid beetle species Monotoma (s. str.) testacea Motschulsky, which develops in decomposing plant matter. Adults and larvae were fed with baker’s yeast under laboratory conditions; this food source allowed for successful breeding of several generations. Detailed and illustrated descriptions of all immature stages are given. It is suggested that simple, pointed setae may represent a diagnostic character for Monotoma (s. str.), whereas clavate setae characterize Monotoma (Gyrocecis). Only minor differences in the number and patterns of setae were found between first, second and third larval instars, supporting observations of previous authors. Morphological differences are listed to distinguish between the three larval instars. An arrow-head aggregation of coarse asperities on the frontal region of the L1 larva, lacking in older instars, is hypothesized to be an egg-burster. Only 34–42 days elapsed from egg laying to emergence of the adult; the egg stage lasted 5–6 days; L1 larvae 2–3 days; L2 3–5 days; L3 2–5 days; the immovable prepupal stage 12–13 days; and the pupa 7–10 days. One female laid 1–5 eggs daily, averaging ~1.5 egg per day during her entire life; the total number of eggs in two independent cultures produced by one female accompanied by one male was 57 and 94.

Successively expressed cuticular protein genes at the prepupal stage in wing discs of Bombyx mori

Background We classified cuticular protein genes expressed at prepupal stage in wing discs of Bombyx mori into six groups according to their developmental expression and ecdysone responsiveness. Their expression pattern is suggested to be regulated by ecdysone-responsive transcription factors, whose transcripts showed resemblance with those of cuticular protein gene expression. Result Group1 and Group2 CP genes showed peak expression at stage W2. Group3 CP genes showed high expression at stage W3E and W3L and were upregulated by 20E addition, showing a peak 12 h after 20E pulse treatment. Group4 CP gene transcripts started expression from stage V5 and peaked at stage W3L. Some genes showed significant increase 4 or 6 h after 20E addition and were induced 6 h and showed a peak 18 h after the 20E pulse treatment. Group5 CP gene transcripts peaked at the same stage W3L. Some Group5 genes showed significant increase 6 h after the 20E addition, while others were not induced by the 20E addition. These different sub-groups showed different expression profiles in the feeding stage. Transcripts of this group genes were induced 12 h and showed a peak 18 h after the 20E pulse treatment. Group6 CP genes peaked at the stage P0, were not induced by the 20E addition, and showed a peak 24 h after the 20E pulse treatment. Group3, 4, 5, and 6 CP genes are suggested to be regulated by BHR4, BR-C, E74A, and βFTZ-F1, respectively. ERTFs showed different responsiveness to 20E concentration. BR-C was most and E74A was least insensitive. The addition of cycloheximide inhibited BR-C, E74A, and βFTZ-F1 expression depending on the length of treatment after ecdysone pulse treatment, which suggests that BHR4 induced BR-C, E74A, and βFTZ-F1. Conclusion Expression patterns of CPs were determined by the ecdysone-responsiveness and the related ERTFs expressed in the prepupal stage in B. mori wing discs.

Morphology of the immature stages of Panorpa qinlingensis (Mecoptera: Panorpidae) with notes on its biology

The scorpionfly Panorpa qinlingensis Chou & Ran is described and illustrated in detail for its immature stages, including egg, larva, and pupa. The egg is oval with chorion decorated with irregular polygonal network. The larva is eruciform and peripneustic, bearing eight pairs of abdominal prolegs. A pair of prominent compound eyes are present on head. The first instar larva differs from later instars in possessing a prominent egg burster on frons and with clavate setae. The pupa is exarate and decticous, taking the shape of the adults. The scorpionfly is bivoltine, overwintering as prepupal stage in the soil. The durations of the egg, larval, and pupal stages are 5–9 d, 19–27 d, and 8–18 d respectively for the first generation. Adults emerge from mid May to early June and from late July to mid August in the Micang Mountain, central China.

Comparative Performance of Helicoverpa armigera (Lepidoptera: Noctuidae) on Chickpea and Faba Bean

Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) is one of the most economically important agricultural pests of chickpea in Asia and Africa. Though most of the H. armigera biology was studied on chickpea, yet better understanding on fababean was still important. The present study was conducted to better understand the life cycle of H. armigera reared on chickpea and faba bean under laboratory conditions via the development of age-stage life tables. The results of life table study indicated that the highest survival rate was during the late larval instar on both hosts followed by early instars. High mortality was during prepupal stage on chickpea and during the 5th larval instar on faba bean. Total larval period was 15.8 days on chickpea and 15.1 days on faba bean. Larvae reared on chickpea exhibited the longest (14.9 days) period of mean total pupal and pre-oviposition durations. Maximum fecundity and eggs viability were recorded from insect reared on chickpea. The current result revealed that chickpea was the more suitable host for reproduction and survival of H. armigera than faba bean under laboratory condition.

Effect of Temperature Treatment during Development of Osmia rufa L., on Mortality, Emergence and Longevity of Adults

The red mason bee (Osmia rufa L.) is a univoltine solitary species of the Osmia genus. This bee is reared on a commercial scale and used as a managed alternative pollinator. We intended that the results of our study would improve the management of this bee so as to synchronise their flying period with the blooming of crops. In the spring, we moved newly occupied nests of the red mason bee to a laboratory and placed them in incubators. Immature development was examined at three constant temperatures, 20°C, 25°C, and 30°C. Selected nests were opened to monitor the subsequent developmental stages. The remaining bees were wintered in nests stored at cool temperature (4°C). In April, we removed the insects from the nests and began incubation at 25°C to establish the emergence time of adult individuals. To determine the survival rate of adult bees, we moved the emerged specimens to cages, where they were fed and kept until death. Temperature increase generally reduced immature development time. But this tendency was not observed in the prepupal stage. During ontogeny the highest mortality rate was observed in wintering adult insects at developmental temperatures of 25°C and 30°C. Bees developing at constant temperatures emerged faster during spring incubation in comparison to those developing in natural conditions. Constant developmental temperatures decreased the survival rate of females as post-emergence adult insects. The survival rate of males was lower at the developmental temperature of 30°C.

Morphology of the Preimaginal Stages ofLasioptera donacisCoutin (Diptera: Cecidomyiidae), a Candidate Biocontrol Agent for Giant Arundo Cane

The larval stages ofLasioptera donacisCoutin consist of three instars which develop within the mesophyll of the leaf sheaths ofArundo donax(L.) (Poaceae). The larvae feed aggregatively on mycelia of an ambrosia fungus. The third instars are similar to other members of the genus except for a three-pronged spatula (typically two-pronged) and five lateral papillae (typically four) and with a nonbristled first instar. A related species,L. arundinis(Schiner) which breeds on fungus inPhragmites(Poaceae), also has a three-pronged spatula and five lateral papillae but has a bristled first instar. The third instar ofL. donacishas a feeding and a nonfeeding prepupal stage. Papillae associated with the spatula are sensory organs, sensilla chaetica, sensilla trichodea, and sensilla ampullacea, perhaps related to extraoral digestion of the fungal mycelia. Pupation occurs in the host plant within a silken cocoon. Egression of the adult is through an escape hatch excavated by the third instar.

Delimitation and description of the immature stages of a pollinating fig wasp, Ceratosolen solmsi marchali Mayr (Hymenoptera: Agaonidae)

The mutualism between fig trees and their wasp pollinators is a model system for many ecological and evolutionary studies. However, the immature stages of pollinating fig wasps have rarely been studied. We monitored developing fig wasps of known ages and performed a series of dissections at 24 h intervals to identify key developmental traits of Ceratosolen solmsi marchali Mayr (Hymenoptera: Agaonidae), a pollinator of Ficus hispida L. (Moraceae). We identified where in the Ficus ovary eggs were deposited and time to hatch. We were also able to identify the timing and key underlying characters of five larval instars, three sub-pupal stages, and a single prepupal stage. We provide detailed morphological descriptions for the key stages and report some behavioral observations of the wasps in the several developmental stages we recorded. Scanning electron microscope images were taken.

Effect of ionizing (gamma) and non-ionizing (UV) radiation on the development of Trichogramma euproctidis (Hymenoptera: Trichogrammatidae)

The potential of using gamma and ultraviolet radiation as an alternative treatment to increase the efficiency of Trichogramma euproctidis (Girault 1911) (Hymenoptera: Trichogrammatidae) was investigated in the laboratory. The developmental and adult stages of T. euproctidis were exposed to gamma radiation of different doses (0-30 Gy) and ultraviolet radiation of 254 nm wavelengths (UV-C) for different durations (0-10 min) to assess their effect on each of the instars and their potential in breaking the developmental cycle of the egg parasitoid. The LD50 values for eggs, prepupae, pupae and adults were 8.1, 10.0, 22.7 and 9.5 Gy for gamma radiation and 9.5, 0.12, 2.0 and 11.9 min for UV radiation, respectively. The pupa and adult stages were more radioresistant to both gamma and UV radiation. The most interesting and unexpected result obtained for the prepupal stage was that UV radiation has a greater effect on prepupal stages than gamma radiation.