In vitro study of lipid metabolism in the mealworm larval fat body

Lipid metabolism in Tenebrio larval fat body has been studied in vitro. Lipid release required the presence of diluted hemolymph in the incubation medium. This time-dependent release of lipid was strongly stimulated in a dose-dependent manner by Tenebrio corpora cardiaca (CC) extracts or synthetic adipokinetic hormone (AKH I). Furthermore, some glycerol was released when larval fat body was incubated without hemolymph, and this phenomenon was also dose dependent for added CC extracts. Lipid synthesis was estimated in vitro by following the incorporation of radioactivity from [6-¹⁴C] glucose into fatty acids. Lipogenesis occurred in the absence of added carbohydrates in the medium, but it was stimulated by the addition of glucose, and especially trehalose (10 mg ml^?1). Intestinal insulin-like peptide (ILP) also stimulated in vitro lipogenesis in a dose-dependent fashion. We conclude that lipolytic and lipogenetic activities of larval mealworm fat body in vitro are effectively under hormonal control.     

灭幼脲引起两种幼虫表皮组织病变的显微观察

本文研究了灭幼脲引起黄粉(虫甲)(Tenebrio mclitor)和粘虫(Mythimna separata)幼虫的中毒征象和组织学病变.低剂量能引起幼虫蜕皮障碍,但看不到明显的组织学病变.高剂量处理,不仅引起了严重的中毒征象,而且伴有明显的组织学病变:内表皮生长停滞,真皮细胞排列异常,在内表皮和真皮细胞之间出现附加层和球状颗粒.对这些现象进行了较细致的讨论.     

The Linnaean fish collection in the Zoological Museum of the University of Uppsala

Specimens of fishes preserved in the Zoological Museum, University of Uppsala, which are believed to have been examined by Linnaeus, are listed. Most of these were originally given to the University in several donations by benefactors of the Academy and were described by Linnaeus in dissertations defended by students. Some specimens, however, are believed to have originated from Linnaeus's own collection. Many of the specimens have type status and this is discussed together with notes on other surviving Linnaean fish specimens.     

Crustacean cardioactive peptide-immunoreactive neurons in the ventral nerve cord and the brain of the meal beetle Tenebrio molitor during postembryonic development

Summary By use of an antiserum against the crustacean cardioactive peptide (CCAP) several types of bilaterally symmetrical neurons have been mapped quantitatively in the ventral nerve cord and in the brain of the meal beetle, Tenebrio molitor. The general architecture of these neurons was reconstructed from peroxidase-antiperoxidase-labelled whole-mount preparations. From the subesophageal to the seventh abdominal ganglia two types of neurons show a repetitive organization of contralateral projection patterns in each neuromere. The first type has few branches in the central neuropil and a distinct peripheral projection. The second type is characterized by an elaborate central branching pattern, which includes ascending and descending processes. Some of its peripheral branches were found to supply peripheral neurohemal areas. In the protocerebrum, 10 CCAP-immunoreactive neurons occur with projections into the superior median protocerebrum and the tritocerebrum. Immunopositive neurons were mapped in larval and various pupal stages, as well as in the adult. All types of identified neurons were found to persist throughout metamorphosis maintaining their essential structural and topological characteristics. The CCAP-immunoreactive neurons of T. molitor are compared with those described for the locust. Putative structural homologies of subsets of neurons in both species are discussed.     

Ejaculate size varies with socio-sexual situation in an insect

Abstract.

• 1 Males operate within a finite energy budget and cannot produce limitless supplies of sperm. On the other hand, when a female mates with a second male while still containing fertile sperm from a rival male, selection should favour the male that inseminates more sperm. Optimal strategy should thus be for males to exercise discretion in the allocation of sperm to individual females. Assuming the outcome of sperm competition to be based on either the raffle or kamikaze principles, the sperm competition hypothesis predicts a positive association between the probability that the sperm will find themselves in competition with sperm from rival males and the number of sperm inseminated.
• 2 The beetle, Tenebrio molitor L., behaves in accordance with this hypothesis. Males accompanied by a rival male before and during mating inseminate more sperm per ejaculate than unaccompanied males. Accompanied males are also faster to initiate mating and more likely to show post-copulatory guarding. Adjustment of number of sperm inseminated was shown by males subjected to both long-term (5 days) and short-term (5 min) exposure to potential intrasexual competitors. Individual males exposed to both levels also demonstrated the ability to adjust their ejaculate according to socio-sexual situation.
• 3 We conclude that male T.molitor adjust the number of sperm they inseminate according to some perception of the risk of sperm competition.

     

The Site Specificity of Two Species of Gregarina in Tenebrio molitor Larvae

The site specificity of the apicomplexans Gregarina cuneata and Gregarina sleini , in larval Tenebrio molitor was investigated. Gregarina cuneata was found to inhabit the anteriormost region of the larval midgut, while G. steini was restricted to the posterior portion of the intestine. The site specificity of the pair was conserved in single and concurrent infections. Interspecific interactions do not seem to be presently responsible for the resource partitioning by the 2 gregarine species. Key words. Gregarina, site specificity, Tenebrio molitor.     

鲤鱼精子超微结构的研究

鲤鱼精子由头部,中片和尾部组成,头部的细胞核卵形,染色质致密。核中有些小空隙,空中的电子致密物质存在。中片紧连在核的后端。中片由中心粒复合体和袖套组成。中心粒复合体位于核后植入窝中,袖套一侧肥厚,一侧狭窄,袖套中有线粒体和囊泡。囊泡有二类,一类含有电子致密物质;另一类无电子致密物质。近袖套内膜处的细胞质中还存在着与内膜平行的膜,精子尾部从袖套腔中伸出。尾部的轴丝与基体相接。尾部的近核端多有许多囊泡     

温度对黄粉虫成虫繁殖的影响

黄粉虫是多种小型经济动物的常用优良饵料,本试验在20.1℃,24.0℃、28.5℃、31.7℃和36.5五种恒温下饲养该成虫结果,成虫寿命平均分别为63.0、54.2、38.8、38.0和26.1天;每雌平均产卵量则分别为200.3、207.3、122.3、115.8和81.2粒,成虫平均生产1g卵消耗麸皮量分别为2.66、2.00、2.19、2.14和4.15g。结果说明人工繁殖黄粉虫的成虫期温度以24℃为最适宜。