ヒトメゲトビムシTomocerus minutus TULLBERGの発生 : III.統計的処理による発育段階の解析

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For the purpose of obtaining knowledge on the seasonal succession of Tomocerus minutus TULLBERG. collections were made once a month from May to October in 1959 in the Cryptomeria forests of "Suzuranyama" near Namioka, Aomori Prefecture. Experiment stations of constant areas (Table 1) were settled and all individuals of different developmental stages were collected from every station and preserved in 90 per cent alcohol. More than one hundred individuals picked up at random were submitted under microscopical measurement. For the sake of deducing the seasonal change of structure of colonies and the number of instars of this insect, the frequency concerning the length of the head and the 3rd abdominal segment were invesigated monthly. The relative growth in the body segments during development was calculated by applying the data of measurment to the Huxley's formula. The formula can be expressed as [numerical formula], where x is equal to the length of the insect; y is the length of a certain segment; k is an initial growth index; α is the growth constant. If the formula is expressed logarithmetrically [numerical formula] 1. By analyzing the data (Figs. 3A, 4A) it became evident that all of the individuals caught in May were the insects which hatched out last year and overwintered. Although they belonged to the various stages of development, the group of individuals of ca. 3.15mm body length (ca 600μ in head length and ca 540μ in abd. III) occupied the considerable high percentage. 2. In the colony of June there appeared two high peaks at the points of ca. 3.15mm body length (630μ in head and 540μ in abd. III) and ca. 2.85mm body length (580μ in head and 470μ in abd. III) on the horizontal axis as shown in figs. 3B and 4B. On the other hand, the colonies of the newly hatched larvae became gradually evident. 3. To consider the colonial succession by the data of July, the colonies of the larger individuals than 3.15mm in body length became rapidly low in the percentage, and they were replaced by new colonies represented by the four developmental stages. Namely, this rapid breakdown of the colonies of larger individuals seems to show that the natural mortality of the insect comes immediately after the reproductive acitvity. 4. In the colony of August, the tendency seen in the colony on July is remarkably stressed, that is to say, the colony of larger individuals is destroyed into several low peaks. 5. Summing up the frequencies of May to August mentioned above, it is assumed that Figs. 3T and 4T theoretically contain the necessary individuals for this period, and, at the same time, they are approximately expected to express the status of the life cycle of this insect. 6. Taking into consideration the knowledge about the histological examination of the gonads, the individuals of about 3.15mm body length are considered to be the pre-reproductive or reproductive adults. And it is also clarified that the insect has at least eight instars to the sexual maturity and newly hatched larvae have six (rarely to eight) ecdysis before entering hibernation (Table 3). Although nearly all the adults die soon after the reproduction, some survive and lay eggs until September, having one or more moultings. 7. Fig. 8 shows the proportional changes of the body segments during the postembryonic development, the body growth grandient. Two growth centra-one in the thorax and one in the abdomen-can be noted. With the greatest certainly the growth centre in the abdomen corresponds to the growth of gonads; the growth center in the thorax is probably due to a gradually increased proportional growth of the thoracic musculature.
社団法人日本動物学会の論文
1962-03-15

ヒトメゲトビムシTomocerus minutus TULLBERGの発生 : III.統計的処理による発育段階の解析

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