西藏地区有瓣蝇类记述(三)花蝇科七新种描述

本文报道采自西藏的有瓣蝇类7个新种,均属花蝇科。正模标本保存在中国科学院上海昆虫研究所。 银额泉种蝇Pegohylemyia argyrometopa,新种（图1—3） 雄:体长6毫米。复眼裸,额宽约为前单眼宽的2倍,间额黑,间额鬃1,下眶鬃7—8,侧额及侧颜黑色上具银白色粉被,侧颜宽为触角第三节宽的4/3倍,触角黑,第三节长为宽的2倍,芒具毳毛,最长毛与芒基宽相等,颊高为眼高的1/5,银白色粉被明显,上倾口缘鬃3行,下颚须黑,中喙具粉被,长为高的4倍,口上片与额齐,后头背区有小毛。     

Genetic Variation at Structural Loci in the Glossina morsitans Species Group

Gene diversity was investigated in four taxa of tsetse flies (Diptera: Glossinidae) including Glossina morsitans morsitans, G. m. centralis, G. swynnertoni, and G. pallidipes. Histochemical tests were performed for 35–46 isozymes. Polymorphic loci were 20% in G. morsitans morsitans, 32% in G. m. centralis, 17.6% in G. swynnertoni, and 26% in G. pallidipes. Mean heterozygosities among all loci were 6.6% in G. morsitans morsitans, 6.0% in G. m. centralis, 7.1% in G. swynnertoni, and 6.8% in G. pallidipes. Allozyme gene diversities were considerably less than those reported for many Diptera. The low gene diversities are probably related to small effective population sizes.     

Genetic and molecular investigations on the endogenous mobile elements of non-drosophilid fruitflies

A syndrome of abnormal genetic effects, resembling Drosophila hybrid dysgenesis, occurs in Ceratitis capitata when strains of different origin are mated. The pattern of abnormal traits observed appears to be the phenotypic expression of a complex interacting dysgenic system of inducer and suppressor effects; probably more than one system is activated in the crosses. This suggests that different systems of mobile elements occur in different strains and populations of C. capitata. Using a PCR primer specific to the ITR sequence of a deleted element, full length mariner elements were isolated from C. capitata, Ceratitis rosa, and Trirhithrum coffeae. Very high similarities were found in inter- and intraspecific comparisons of the elements. The majority of these elements contained deletions and frame-shifts. However, one clone Ccmar1.18, from C. capitata, was found to possess an uninterrupted ORF coding for 338 amino acids with ∼60% similarity to the Mos1 element of Drosophila mauritiana. Database searches and phylogenetic analyses showed that the mariner elements isolated in the present study are representatives of Robertson's mellifera mariner subfamily. The copy numbers of the elements within each species are very different, ranging from about 10 in T. coffeae to 5000 in C. rosa. This revised version was published online in August 2006 with corrections to the Cover Date.     

Control of the mushroom pests Lycoriella auripila (Diptera: Sciaridae) and Megaselia halterata (Diptera: Phoridae) by Steinernema feltiae (Nematoda: Steinernematidae) in field experiments

The nematode Steinernema feltiae (Nematoda: Steinemematidae) was tested for its ability to control two main mushroom pests i.e. the sciarid Lycoriella auripila (Diptera: Sciaridae) and the phorid Megaselia halterata (Diptera: Phoridae) in growing-rooms filled with spawned compost. A clear difference between female and male sciarid control was observed. A nematode application 1 day after casing preceded by an application 1 day before casing on the compost caused an almost complete control (97%) of the F1-generation of female sciarids. The F2-generation of females was similarly controlled (95%) by an application 7 days after casing. A dosage of 1 × 10⁶nematodes m^-2was found to be equally effective as higher dosages. Diflubenzuron remained active throughout entire the cropping period with high sciarid mortality rates varying from 72% to 99%. Phorid control was variable and seemed to depend on the presence of sciarids. In one occasion the control rate of F2-generation phorid larvae was 75% and was possibly caused by the presence of new infective juvenile nematodes recycled in F2-generation sciarid larvae. Diflubenzuron did not significantly reduce phorid numbers.     

Hosts of Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) from Broome and the Broome Peninsula, Western Australia

Abstract  In the Kimberley region of Western Australia, Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) is only established at Broome. From 1998 to 2001 extensive fruit sampling was carried out at Broome during a trial investigating the eradication of medfly from the Kimberley using the sterile insect technique. Fruit was collected from 82 native and introduced plants growing in and surrounding the town of Broome and held for emergence of medfly. Eighteen plants, including the native tree Terminalia petiolaris , were found to be medfly hosts . On the basis of abundance, fruiting phenology and host suitability, eight species (kumquat Fortunella japonica , mango Magnifera indica , Barbados cherry Malpighia glabra , orange jessamine Murraya paniculata , guava Psidium guajava , Pacific almond Terminalia catapa , blackberry tree Terminalia petiolaris and yellow oleander Thevetia peruviana ) were the most important hosts ensuring medfly survival and population growth. Despite medfly being reared from T. petiolaris , it is likely that medfly can only maintain populations in areas close to human habitation, and eradication from these areas would lead to eradication from the whole Kimberley region.     

Thermal constraints on activity patterns in nectar-feeding insects

ABSTRACT.

• 1 All the insects visiting Tilia and Heracleum flowers showed diel patterns of activity, which could best be explained in terms of weather. Of the recorded parameters, solar radiation gave the best correlations with activity.
• 2 Correlations between activity and radiation depended on the size and colour of particular groups of insects; small bright species visited fully insolated flowers, (r high), while large dark forms visited early and late in the day (r low or negative).
• 3 Consequently mean reflectance and mean weight of foragers showed consistent trends through a day and predictable relations with radiation for both flowers, suggesting that thermal costs are a critical determinant of feeding times.
• 4 By contrast, the nectar reward (as sugar amounts) in flowers was poorly correlated with timing of insect visits, indicating that caloric reward is not limiting; although nectar concentration (only measurable for Tilia) did correlate reasonably well with total visitation.
• 5 The exception to this pattern was Bombus. This endothermic species visited early in the day when nectar was abundant. Thus visits correlated well with reward and negatively with radiation, showing a dependence on high rewards to offset thermoregulatory metabolic costs.
• 6 For most insects foraging appeared to be largely determined by the visitors thermal requirements and the restrictions imposed by avoidance of overheating. Nectar rewards were not critical, and nectar concentration, itself dependent upon climatic parameters, was probably only incidentally correlated with diel patterning for all but the largest (endothermic) insects.

     

Carbohydrate utilization by normal and γ-sterilized Dacus oleae

Non-sterilized adult olive fruit flies were able to survive and reproduce on mannose, glucose, fructose, sucrose, melibiose, trehalose, maltose, melezitose, and sorbitol, out of a series of 23 carbohydrates γ-sterilized flies were able to utilize the same carbohydrates with the exception of melezitose, indicating that sterilization with a 10 Krad dose did not affect their ability to utilize various carbohydrates. Since these carbohydrates are common constituents of the fly's natural food sources, the released sterile flies should be able to survive satisfactorily in the field. The possible presence of three carbohydrases is discussed.