Acoustic behaviour of both sexes of the speckled bush cricket Leptophyes punctatissima

As in other phaneropterine bush-crickets, both male and female Leptophyes punctatissima can stridulate. Stridulation in the female, which had previously been overlooked, occurs in response to the male call. The main frequency of the very brief chirps is around 40 kHz. The male is stimulated to chirp more frequently by receiving response chirps from the female. Unlike most Tettigoniidae the male moves toward the female and is thus dependant on her response signal. Communication can occur over distances of at least 5 m. Some structures involved in stridulation in the female differ from that described in other phaneropterines. The insects used in these experiments were all reared in the laboratory from wild-caught parents. Between forty and fifty different insects were used at various times for laboratory studies on the song, and four different males and three females were used on the field communication experiments. The sexes were kept separate from the moult to adult or for at least 10 days before experiments.     

血管紧张素Ⅱ、心房钠尿肽Ⅲ和血管升压素对大鼠脑片室旁核神经元放电活动的影响

在28个脑片观察了血管紧张素Ⅱ(AGⅡ)、心房钠尿肽Ⅲ(ANPⅢ)和血管升压素(AVP)三种多肽对101个下丘脑室旁核(PVN)神经元单位电活动的影响。脑片灌流AGⅡ(10~(-7)mol/L,3 min)后,28/50个单位(56.0％)放电频率明显增加,5/50个单位(10.0％)放电频率降低,17/50个单位(34.0％)无明显反应。AGⅡ对PVN放电单位的兴奋和抑制作用均可为AGⅡ受体阻断剂saralasin(10~(-6)mol/L)所阻断。脑片灌流ANPⅢ(10~(-7)mol/L,3 min)后,16/26个单位(61.5％)放电频率明显降低,1/26个单位(3.9％)放电频率增加,9/26个单位(34.6％)无明显反应。脑片灌流AVP,(10~(-7)mol/L,3min)后,19/25个单位(76.0％)放电频率明显增加,1/25个单位(4.0％)放电频率降低,5/25个单位(20,0％)无明显反应。在观察这三种多肽对同一PVN神经元的作用时,4个单位对AGⅡ和AVP均产生兴奋反应;2个单位对AGⅡ呈兴奋和被ANPⅢ所抑制;7个单位对AVP呈兴奋,而对ANPⅢ为抑制,未见到既对AGⅡ和AVP呈兴奋,又为ANPⅢ所抑制的单位。结果提示:AGⅡ,ANP和AVP三种多肽都能影响PVN神经元的自发电活动,PVN可能是神经内分泌和植物性功能调节的中枢整合部位之一。     

α-人心房钠尿多肽对大鼠血流动力学的作用

本工作观察了α-人心房钠尿多肽(α-Human atrial natriuretic polypeptide,α-hANP)对麻醉大鼠的血流动力学作用。静脉注射α-hANP(3μg/100g)后,动脉血压(ABP)、左室内压(LVP)、左室 dp/dt(LV dp/dt)、心指数(CI)和总外周阻力指数(TPRI)均明显下降,而心率(HR)无明显变化。切断迷走神经后,α-hANP 降压和 LV dp/dt 下降的程度虽有所减小,但与切断前相比无统计学意义。我们的结果表明,α-hANP 对麻醉大鼠的降压机制,在于外周血管舒张所致的总外周阻力减小,以及心肌收缩性能抑制而引起的心输出量降低。     

Klossiella (Apicomplexa,Klossiellidae) in Petaurid and Macropodid Marsupials in Australia1

Six new species of Klossiella are described in the kidneys of Australian marsupials: Klossiella rufogrisei in Bennett's Wallaby, Macropus rufogriseus; Klossiella rufi in the Red Kangaroo, Macropus rufus; Klossiella thylogale in the Red-Bellied or Tasmanian Pademelon, Thylogale billardierii; Klossiella beveridgei in the Spectacled Hare-Wallaby, Lagorchestes conspicillatus; Klossiella bettongiae in the Tasmanian Bettong, Bettongia gaimardi; and Klossiella schoinobatis in the petaurid Greater Glider, Petauroides volans. It is concluded that the genus Klossiella has radiated widely among Australian marsupials, and that since it is present in American marsupials, it may have an ancient association with the subclass.     

Responses of insect herbivores to sharing a host plant with a hemiparasite: impacts on preference and performance differ with feeding guild

1. Root hemiparasites are common components of many ecosystems and can affect both the biomass and the nutritional quality of the plants they infect. The consequences of these modifications for the preference and performance of three herbivore feeding guilds sharing a host with the hemi‐parasite were examined. 2. It was predicted that as the hemiparasite increased in biomass its impact on the host would increase, as would the indirect impacts on the herbivores. It was also predicted that herbivores from different feeding guilds would respond differently to the presence of the hemiparasite, reflecting the extent to which they utilise resources disrupted by the parasite and hence are in competition with it. 3. The preference and performance of phloem‐feeding aphids, xylem‐feeding spittle bugs, and leaf‐feeding grasshoppers were measured on the host grass species, Holcus lanatus L. (Poaceae), with and without attachment from the hemi‐parasite, Rhinanthus minor L. (Orobanchaceae). 4. The effects of R. minor on the host were dependent on the hemiparasite's stage of growth, being most pronounced when it was at peak biomass. At this stage it caused a significant reduction in the biomass, water content, and total nitrogen content of the host plants. 5. Overall, herbivores benefited from, or preferred, shared host plants more than uninfected plants. The aphid benefited from sharing a host with R. minor, showing increased population growth on, and preference for, parasitised plants. The spittle bug also showed a preference for parasitised plants. The grasshopper, Chorthippus brunneus Thunberg (Orthoptera: Acrididae), did not show a preference for, or a performance response to, parasitised hosts, but it consumed significantly more plant material when caged on parasitised plants. 6. These data support the prediction that invertebrate herbivores responded to changes in host plant traits driven by the hemiparasite, and strongly suggest that these indirect interactions could impact on population and community processes within natural communities.