Potential of Haplothrips brevitubus (Karny) (Thysanoptera: Phlaeothripidae) as a predator of mulberry thrips Pseudodendrothrips mori (Niwa) (Thysanoptera: Thripidae)

The predation potential of Haplothrips brevitubus (Karny) for thrips was evaluated in the laboratory. When second stage larvae of Pseudodendrothrips mori (Niwa) were presented to an adult H. brevitubus at densities of 10, 20, 30, and 40 larvae per cage at 25 °C over 24 h, the number of larvae consumed per day increased with an increasing density up to 30. Predation of H. brevitubus exhibited the type II functional response. The mean development time of the egg, larva, and pupa of H. brevitubus were 4.5, 9.6, and 4.8 days, respectively, at 25 °C. The survival rate from egg to adult emergence was 94.7%. One H. brevitubus larva consumed 41.6 P. mori larvae on average during the total larval period. Adult longevity was 35.2 days in females and 34.6 days in males. The pre-oviposition period was 2.7 days and the oviposition period was 31.5 days. The lifetime fecundity was 120.1 eggs and the mean daily oviposition rate was 3.6 eggs. Calculated mean generation time (T) was 29.5 days, intrinsic rate of natural increase (r_m) was 0.162, and net reproductive rate (R₀) was 56.5. The r_m value of H. brevitubus was higher than that of Thrips palmi Karny and almost equal to that of Frankliniella occidentalis (Pergande). These results indicate that H. brevitubus has good potential as a predator of P. mori and is likely to be useful for controlling thrips.     

中国简管蓟马属一新种记述(缨翅目:管蓟马科)

本文记述采自内蒙古的简管蓟马属Ｈａｐｌｏｔｈｒｉｐｓ Ａｍｙｏｔ ｅｔ Ｓｅｒｖｉｌｌｉｅ一新种，即短鬃简管蓟马Ｈ．ｂｒｅｖｉｓｅｔａ ｓｐ．ｎｏｖ。     

A two-phase open-field test to evaluate the host-specificity of candidate biological control agents for Heliotropium amplexicaule

This paper describes an open-field host-specificity test conducted to make a preliminary evaluation of the safety of four candidate agents for the biological control of Heliotropium amplexicaule, an invasive weed of South American origin. These agents were a leaf-eating beetle, Deuterocampta quadrijuga, a flea-beetle, Longitarsus sp., that feeds on leaves as an adult and roots as a larva, a shoot-feeding thrips, Haplothrips heliotropica, and a cell-sucking bug, Dictyla sp. During the first phase of the experiment, the four agents were given a choice between the target weed and six species of nontarget plant of varying degrees of phylogenetic relatedness. All four species were found to feed and reproduce on only H. amplexicaule and the closely related H. nicotianaefolium (a member of the same section of the genus Heliotropium). No plants outside this genus were attacked. For the second “no-choice” phase, the host-plants used in Phase 1 were cut, forcing the insects to use either other plant species within the plots, emigrate, or die of starvation. Heliothrips heliotropica disappeared rapidly from the plot, while D. quadrijuga persisted for several days on Heliotropium arborescens with some exploratory nibbling and then disappeared. Host-choice behavior of these species therefore remained unchanged, even in the absence of the primary host-plants. In contrast, adults of Longitarsus sp. rapidly colonized and fed on H. arborescens when the preferred hosts were removed. It therefore demonstrated a wider host-range under these more extreme conditions. In fact, on some plots, feeding commenced on H. arborescens before the “no-choice” phase, once the two preferred Heliotropium species were heavily damaged by these insects. The two-phase test is shown here to be a useful way of measuring host-choice behavior under “normal” conditions of choice and under more extreme conditions, such as it might occur were an agent to locally destroy the target weed following its release. It therefore provides a more refined assessment of the risk that would be posed to nontarget plants by the release of weed biological control agents.     

中国简管蓟马属TRYBOMIELLA亚属一新纪录种记述(缨翅目,管蓟马科)

根据前翅间插缨的有或无,简管蓟马属Haplothrips常分成两亚属,即指名亚属Haplothrips和无间插缨亚属Trybomiella.目前中国已知18种简管蓟马均属于指名亚属Haplothrips.记述了采自菊科鬼针草花上的无间插缨亚属Trybomiella 1新纪录种,钳端简管蓟马Haplothrips(Trybomiella)articulosus(Bagnall),该种原产于非洲大陆.中国Trybomiella亚属曾记载有2种,其中顶简管蓟H.(T.)apicalis(Bagnall)已转移到Plicothrips属,而色带简管蓟马H.(T.)aurocingulatus Pelikan是Dyothrips pallescens(Hood)的同物异名.首次报道该亚属在中国的分布.研究标本保存在华南农业大学昆虫学系昆虫标本室.