An orb‐weaver spider exploits an ant–acacia mutualism for enemy‐free space

Exploiters of protection mutualisms are assumed to represent an important threat for the stability of those mutualisms, but empirical evidence for the commonness or relevance of exploiters is limited. Here, I describe results from a manipulative study showing that an orb‐weaver spider, Eustala oblonga, inhabits an ant‐acacia for protection from predators. This spider is unique in the orb‐weaver family in that it associates closely with both a specific host plant and ants. I tested the protective effect of acacia ants on E. oblonga by comparing spider abundance over time on acacias with ants and on acacias from which entire ant colonies were experimentally removed. Both juvenile and adult spider abundance significantly decreased over time on acacias without ants. Concomitantly, the combined abundance of potential spider predators increased over time on acacias without ants. These results suggest that ant protection of the ant‐acacia Acacia melanocerus also protects the spiders, thus supporting the hypothesis that E. oblonga exploits the ant–acacia mutualism for enemy‐free space. Although E. oblonga takes advantage of the protection services of ants, it likely exacts little to no cost and should not threaten the stability of the ant–acacia mutualism. Indeed, the potential threat of exploiter species to protection mutualisms in general may be limited to species that exploit the material rewards traded in such mutualisms rather than the protection services.     

Three new species of the myrmecophilous genus Doryloxenus from China (Coleoptera,Staphylinidae, Aleocharinae)

Three new species of the pygostenine genus Doryloxenus Wasmann, viz., Doryloxenus aenictophilus sp. n. (from Zhejiang), Doryloxenus tangliangi sp. n. (from Zhejiang), and Doryloxenus songzhigaoi sp. n. (from Yunnan), are described, illustrated and distinguished from the Asian congeners. An identification key to the Chinese species is given.     

Host record of the myrmecophilous carabid genus Cryptocephalomorpha (Coleoptera: Carabidae: Pseudomorphinae) with description of a new species from Thailand

Cryptocephalomorpha siamensis sp. nov. is described from Thailand. The type series was collected from a nest of myrmicine ant, Pheidole singaporensis, which is the first exact host record of the genus Cryptocephalomorpha. Collecting circumstances and observed behavior are reported.     

Tetramorium tsushimae, a New Invasive Ant in North America

Combining molecular and morphological evidence, an invasive ant in Missouri and Illinois, USA, is identified as Tetramorium tsushimae Emery, 1925, a polygynous-polycalic species native to East Asia. T. tsushimae is recorded as invasive for the first time. RFLP and worker morphometrics provide tools for reliable determination. Mitochondrial DNA data reveal the probable geographic origin of the invasive populations to be Japan. The first two authors contributed equally to this work.     

Host propagation permits extreme local adaptation in a social parasite of ants

The Red Data Book hoverfly species Microdon mutabilis is an extreme specialist that parasitises ant societies. The flies are locally adapted to a single host, Formica lemani , more intimately than was thought possible in host–parasite systems. Microdon egg survival plummeted in F. lemani colonies > 3 km away from the natal nest, from c. 96% to 0% to < 50%, depending on the hoverfly population. This is reflected in the life-time dispersal of females, measured at < 2 m, resulting in oviposition back into the same ant nests for generation after generation. To counter destabilizing effects on the host, Microdon manipulates the social dynamics of F. lemani by feeding selectively on ant eggs and small larvae, which causes surviving larvae to switch development into queens. Infested colonies rear double the number of new queens, thus propagating the vulnerable local genotype and compensating for damage to the host colonies. The consequences of such extreme host specificity for insect conservation are discussed.     

The Importance of Ants and High-Shade Management to Coffee Pollination and Fruit Weight in Chiapas, Mexico

Recent reports show importance of pollinators to coffee and importance of ants as pollinators or floral protectors in many systems. Arthropod and pollinator diversity, however, declines with management intensification of coffee (Coffea arabica) agroecosystems. We investigated influences of both flying pollinators and ants on coffee fruit set and fruit weight in one high-shade (high-biodiversity) and one low-shade (low-biodiversity) coffee farm in Chiapas, Mexico through exclusion experiments. Contradictory to previous reports, flying pollinators alone did not affect coffee fruit set or fruit weight. Individual fruit weights, however, were higher on branches with both ants and flying pollinators (1.78 g ± 0.312 (SE)) compared to branches without ants (1.03 ± 0.029) or branches without ants or flying pollinators (1.05 ± 0.049), but only in the high-shade site. Although the mechanisms producing higher fruit weights are unknown, we discuss how ants or ant-flying pollinator interactions under high-shade coffee management may contribute to increased fruit weight and the implications of high-shade management for both sustainable coffee production and biodiversity conservation.     

豫东平原蚂蚁群落结构及物种多样性

在2006年4、5月对豫东平原5种生境(人工林地、荒地、农田区、居民区和山丘)的蚂蚁进磊了广泛的调查,共获得蚂蚁62703只,隶属于5亚科,18属,43种.结果表明:5种生境中蚂蚁群落种类、组成和多样性等指标均不相同;人为干扰越强的生境,蚂蚁群落多样性指数越低;质量和异质性越高的生境,蚂蚁群落多样性指数越高.     

成都地区居室庭院蚂蚁种类调查

2005～2008年对成都地区居室庭院环境中的蚂蚁种类进行了调查,共发现3个亚科12属的蚂蚁26种,其中,切叶蚁亚科Myrmicinae的蚂蚁无论种类和数量在成都地区都占绝对优势,优势种为印度大头蚁Pheidole indica Mayr和史氏盘腹蚁Aphaenogaster smythiesi Forel.居室庭院蚂蚁在成都地区的分布以印度大头蚁Pheidole indica Mayr、史氏盘腹蚁Aphaenogaster smythiesi Forel和亮立毛蚁Paratrechina vividula Nylander的分布最广.