Benzoic acid conjugation in tuatara

The excretion and metabolism of orally administered [¹⁴C]-labelled benzoic acid (100 mg/kg) was examined in the reptile Sphenedon punctatus (tuatara). The major excreted metabolite was chromatographically and electrophoretically identical with ornithuric acid. Conjugation with glycine or glucuronic acid was not detected. 7–21 percent of the dose was recovered from the urine and faeces, the bulk of the excreted radioactivity being eliminated in the first seven days. Free benzoic acid and conjugates were excreted in the first week but only conjugates could be detected in fauces collected at later intervals. These results are discussed in relation to the taxonomic position of tuatara.     

Seasonal monogamy and multiple paternity in a wild population of a territorial reptile (tuatara)

Investigating the mating system of a population provides insight into the evolution of reproductive patterns, and can inform conservation management of threatened or endangered species. Combining behavioural and genetic data is necessary to fully understand the mating system and factors affecting male reproductive success, yet behavioural data are often difficult to collect for threatened species. In the present study, we use behavioural data and paternity analyses to characterize the mating system of a high density population of a long-lived, ancient reptile (tuatara, Sphenodon punctatus ). We further investigate the phenotypic traits (including body size, body condition, tail length, and ectoparasite load) that affect male reproductive success. Our behavioural data reflect a seasonally monogamous system with low levels of polyandry and polygyny that are consistent with male mate guarding. Male reproduction is highly skewed (only 25–30% of males are successful), and body size is the primary predictor of male reproductive success. Based on the genetic data, multiple paternity was found in only 8% of clutches, and the results of the paternity analyses showed monandrous clutches from socially polyandrous females. Our behavioural and genetic results revealed complexities in female mating patterns that support the potential for cryptic female choice or sperm competition. This warrants further experimental investigation into the mechanisms underlying reptile fertilization and the disparities between social and genetic polyandry in wild populations.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 161–170.     

阿维灭幼脲对马尾松毛虫幼虫的毒力测定

运用阿维灭幼脲生物复合剂对3-4龄的马尾松毛虫幼虫进行毒力测定,用机率分析法求得马尾松毛虫的死亡率与阿维灭幼脲剂量对数—机率直线,建立毒力回归线。研究表明,25%阿维灭幼脲悬浮剂对3-4龄幼虫的致死中稀释浓度为49.6倍液,即LC50=5.04 mg.L-1;阿维灭幼脲悬浮剂与尿素混合剂对3-4龄的致死中稀释浓度为52.5倍液,即LC50=4.76 mg.L-1;25%阿维灭幼脲悬浮剂10倍稀释液对3-4龄马尾松毛虫幼虫的LT50为0.57 d,到50倍稀释液时LT50为7.35 d;25%阿维灭幼脲悬浮剂与尿素混合剂10倍稀释液对3-4龄马尾松毛虫幼虫的LT50为0.71 d,到50倍稀释液时LT为6.13 d,随着浓度稀释倍数的增加,致死中时间延长。研究结果可为今后马尾松毛虫的林间防治提供科学依据。     

Small subunit ribosomal RNA sequence of Henneguya exilis (class Myxosporea) identifies the actinosporean stage from an oligochaete host

Several transmission studies, as well as recent molecular data, have indicated that the two classes Myxosporea and Actinosporea represent different life cycle stages of Myxozoa. To evaluate the life cycles of myxozoa in catfish aquaculture systems, the small subunit (18S) ribosomal RNA gene sequences of Henneguya exilis, a myxosporean from channel catfish Ictalurus punctatus, and an actinosporean (previously designated as Aurantiactinomyxon janiszewskai) from the aquatic oligochaete Dero digitata were determined. The sequences were identical, indicating that H. exilis and the actinosporean are alternate life stages of a single species. This is the first report identifying the actinosporean stage of the genus Henneguya.     

被害马尾松（Pinus massoniana）针叶挥发性物质的提取、鉴定及蚕饰腹寄蝇（Blepharipa zebina）的电生理活性

试验使用动态顶空吸附的方法,提取了被害马尾松(Pinus massoniana)针叶挥发物,并通过气相色谱-质谱联用仪(GC-MS)及标准样品进行鉴定。结果表明,被害马尾松针叶挥发性物质主要包括绿叶挥发物、单萜、含氧单萜及倍半萜等四大类物质;挥发物中以单萜的含量最高,其它3类物质含量较低。通过触角电位图(EAG)技术,测定了23种挥发性物质标准样品的石蜡油溶液对蚕饰腹寄蝇(Blepharipa zebina)雌蝇的电生理活性。结果表明,蚕饰腹寄蝇雌蝇对α-蒎烯、β-蒎烯、长叶烯、莰烯、乙酸冰片酯等的相对触角电位反应值与湿润空气对照相比并无显著差异;雌蝇对其它刺激物的相对触角电位反应值与湿润空气对照相比均存在显著差异。同时测定了雌蝇对8种标样,在5个浓度系列下的剂量-反应,并分析了反应阈值。结果表明,蚕饰腹寄蝇雌蝇对顺-3-己烯-1-醇和里哪醇的反应阈值为0.1μg/μl,对壬醛的反应阈值为1μg/μl,对柠檬烯、α-水芹烯、2,6-二甲基-2,4,6-辛三烯、β-石竹烯4种物质的反应阈值为100μg/μl,而对α-蒎烯,在测试的剂量范围内不存在反应阈值。在确定对蚕饰腹寄蝇有生理活性的物质成分和分析反应阈值的基础上,对寄生蝇类定位寄主的机制进行了讨论。     

Extinction-colonization dynamics structure genetic variation of spotted sunfish (Lepomis punctatus) in the Florida Everglades

The population genetics of aquatic animals in the Florida Everglades may be strongly influenced by extinction and colonization dynamics. We combined analyses of allozyme and microsatellite loci to test the hypothesis that two levels of population structure are present for spotted sunfish (Pisces: Centrarchidae: Lepomis punctatus) inhabiting the Everglades. We hypothesized that annual cycles of marsh dry-down increase local-scale genetic variation through a process of local extinction and colonization; we hypothesized that barriers to gene flow by levee/canal systems create a second, regional level of genetic variation. In 1996 and 1997, we sampled spotted sunfish from 11 Everglades sites that were distributed in three regions separated by levees. We documented patterns of genetic variation at 7 polymorphic allozyme loci and 5 polymorphic microsatellite loci. Most genetic variation was present among local populations, according to both types of genetic markers. Furthermore, samples from marsh sites were heterogeneous, while those from canals were not. These data supported our hypothesis that dry-down events and local population dynamics in the marsh have a significant effect on population genetic structure of spotted sunfish. We found no support for our hypothesis that water-management structures superimpose a second level of genetic structure on this species, possibly because canals obscure historical structure by facilitating gene flow or because the complete canal system has been in place for fewer than 20 generations of this species. Our data suggests a continent-island (canal-marsh) structure of populations with high gene flow among regions and recurrent mixing in marshes from canal and creek habitats.     

A study of the peripheral innervation and muscle fibre types of Ictalurus nebulosus (Lesueur) and Ictalurus punctatus (Rafinesque)

The innervation pattern and fibre types of the axial musculature of two closely related catfish species with differing lifestyles, Ictalurus nebulosus (Lesueur) and I. punctatus (Rafinesque) were investigated. Both fish displayed the multiple innervation pattern in the red muscle. However, the white muscle of I. nebulosus demonstrated terminal innervation while I. puncrurus displayed multiply innervated white muscle fibres. Fibre typing utilizing histochemical techniques for glyco-gen, lipid, succinic dehydrogenase and glucose-6-phosphate dehydrogenase revealed the typical teleostean distribution of red, intermediate and white muscle fibres in both fish. Staining was greatest in the red muscle fibres and least in the white muscle fibres. The white muscle fibres of I. punctatus stained slightly more for lipid than the white fibres of I. nebulosus which may be correlated with a greater aerobic capacity related to lifestyle and possibly innervation.     

不同生境中马尾松毛虫赤眼蜂中间寄主研究(英文)

本文讨论了马毛松毛虫赤眼蜂在混交林、纯林及疏残林三种不同生态环境条件下的中间寄主。试验是在湖南省东部的浏阳县进行。研究结果表明松毛虫赤眼蜂共有103种中间寄主;一年中有两个危险期,在危险期内只有少量的中间寄主存在。