• Journal of Sericultural and Entomological Science
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• v.16 no.2
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• pp.119-125
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• 1974

When the nomal silkworms reached active time of 3rd instar stage both non-moulting larva and normal silkworms from the same rearing tray were collected and fixed. The silkworms in 4th instar stage whose growth was as dwarfish as those in 1st and 2nd instar stages were also collected and fix with the normal silkworms. Non-moulting larva and normal silkworms were morphologically compared and the examined results from the tissue inspection are summarized as follows： 1. In spite of the fact that the normal silkworms reached the active eating time of 3rd instar stage non-moulting silkworms were dwarfish as if they had been reared for two days. Non-moulting silkworms which were observed at the time of 4th instar stage showed no much difference in their growth. 2. There was the tendency that the exuvial gland as was shown in Fig. 1 and 2 was flat cyslidium of ellipse and its size at thorax was small shile the gland at abdomen was big. 3. The exuvial gland at thorax has been reported to be bigger at thoracic base than at dorsal vessel but according to the present it was examined to be irregular. 4. The size of exuvial gland of silkworms in the active eating stage of 3rd instar was from 151.3${\mu}$ (major axis) to 94.5${\mu}$ (minor axis) at prothorax and from 568.6${\mu}$ (major axis) to 495.1${\mu}$ (minor axis) at 7th abdominal segment. The sire oe exuvial gland of non-moulting silkworm was 57.5${\mu}$ (major axis) to 51.3${\mu}$ (minor axis) at prothorax and from 91.5${\mu}$ (major axis) to 75.5${\mu}$ (minor axis) at 5th abdominal segment (see Fig. 1) 5. When the normal silkworms reached 4th instar active eating stage its exuvial gland was compared to that of dwarfish silkworm. The result was that the size of normal silkworm at prothorax was from 252.2${\mu}$ (major axis) to 131.6${\mu}$ (minor axis) and the size of exuvial gland at 7th abdominal segment was from 691.5${\mu}$ (major axis) to 493.4${\mu}$ (minor axis) while the sire of exuvial gland of non-moulting at prothorax was from 71.4${\mu}$ (major axis) to 61.5${\mu}$ (minor axis) and the size of the non-moulting silkworm's 8th abdominal segment was from 94.6${\mu}$ (major axis) to 71.5${\mu}$ (minor axis) (See Table 2) 6. There was a remarkable difference in the from of exuvial gland of non-moulting silkworm. The size of alveolar of the non-moulting silkworm was many times larger compared to that of normal silkworm 7. There was no great difference between secretory cells of normal and non-moulting silkworms but the granular type exuvial gland was small in sire compared to that of normal silkworm.

• Parasites, Hosts and Diseases
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• v.51 no.6
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• pp.633-636
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• 2013

Angiostrongylus cantonensis is a parasitic nematode that needs to develop in different hosts in different larval stages. Freshwater snails, such as Pomacea canaliculata, are the intermediate host, and rats are the definitive host. Periodic shedding of the cuticle (moulting) is an important biological process for the survival and development of the parasite in the intermediate and definitive hosts. However, there are few studies on the cuticle alterations between different stages of this parasite. In this study, we observed the ultrastructural appearance and changes of the cuticle of the 2nd/3rd stage larvae (L2/L3) and the 3rd/4th stage larvae (L3/L4) using a scanning electron microscope. We also first divided L2/L3 into late L2 and early L3. The late L2 lacked alae, but possessed a pull-chain-like fissure. Irregular alignment of spherical particles on the cuticle were noted compared to the L3. Alae appeared in the early L3. The old cuticle turned into a thin filmlike structure which adhered to the new cuticle, and spherical particles were seen regularly arranged on the surface of this structure. Regular rectangular cavities were found on the surface of L3/L4. The caudal structure of L3/L4 was much larger than that of L3, but caudal inflation, such as seen in L4, was not observed. These results are the first to reveal the ultrastructural changes of the cuticle of A. cantonensis before and after moulting of L2/L3 and L3/L4.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.479-487
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• 2021

This study investigated the life history of the plum sawfly Monocellicampa pruni Wei, 1998 through field observations and laboratory experiments. M. pruni is a univoltine, complete metamorphosis species with five instars at the larval stage. Adults emerge from the soil around mid-March when Japanese plum trees are in their flowering period. The adults deposit one (rarely two) egg(s) under the epidermis layer of the calyx. After hatching, the larva soon burrows into the fruitlet, consumes the endocarp and remains inside the fruit within its four-time moulting transitions before reaching full growth. At maturity (in May), the larva leaves the infested fruitlet through an exit hole and burrows into the soil at a depth of 2 - 11 cm for spinning its cocoon and hibernates until the next spring as the larval form. Under laboratory conditions (T = 20℃; RH = 40 - 60%), the male lived for a slightly shorter period than the female, 6.03 ± 0.40 and 7.55 ± 0.45 days, respectively. A female could produce 30.29 ± 4.50 eggs in her lifespan. In the field, the duration of the egg was approximately 10 - 11 days and that of the larva was approximately 31 - 34 days.