Clonal composition of colonies of a eusocial aphid, Ceratovacuna japonica

High degrees of relatedness among colony mates and kin recognition ability are important factors maintaining eusociality. However, in eusocial aphids, clone mixing between different colonies is reported to occur frequently, suggesting a lack of kin recognition. Studies investigating the clonal composition of eusocial aphid colonies have focused on the aphid generation on the primary host plant (gall generation). To test whether clone mixing also occurs in open colonies of eusocial aphids on their secondary host plants (open-colony generation), we carried out an amplified fragment length polymorphism analysis to investigate clonal composition within colonies of the eusocial aphid Ceratovacuna japonica. The results showed that clone mixing occurred frequently in open-colony generation.ArticleSOCIOBIOLOGY. 62(1):116-119 (2015)journal articl

Individual and collective dynamics of self-propelled soft particles

Deformable self-propelled particles provide us with one of the most important nonlinear dissipative systems, which are related, for example, to the motion of microorganisms. It is emphasized that this is a subject of localized objects in non-equilibrium open systems. We introduce a coupled set of ordinary differential equations to study various dynamics of individual soft particles due to the nonlinear couplings between migration, spinning and deformation. By introducing interactions among the particles, the collective dynamics and its collapse are also investigated by changing the particle density and the interaction strength. We stress that assemblies of self-propelled particles also exhibit a variety of non-equilibrium localized patterns

Ground ant fauna in a Bornean dipterocarp forest

The ant fauna of the forest floor was studied in a Bornean lowland dipterocarp forest using honey baits. A total of 51 species belonging to 23 genera was collected from 90 (45 daytime + 45 night) baits set on the ground surface and 90 (45 daytime + 45 night) baits set on tree trunks at 0.5-1.0 m above the ground. Collected species represented only 22% of the total ant species so far known from this area using a combination of several collection techniques. Although some species (Pheidole spp., Camponotus gigas, Lophomyrmex longicornis, etc.) are more frequently attracted than others, the frequency occurrence in these species was much lower than in the dominant species in warm temperate evergreen forests in Japan. Baits put on the ground surface attracted more ant species than those on tree trunks (35 vs. 25 spp.), and only 9 species were common to both types of habitat. Daytime and night baits attracted nearly the same number of ant species (34 vs. 31), only 14 being common to both time zones. Various aspects of ant diet and activity pattern are discussed.ArticleRaffles Bulletin of Zoology. 44(1): 253-262(1996)journal articl

Clonal composition of colonies of a eusocial aphid, Ceratovacuna japonica

High degrees of relatedness among colony mates and kin recognition ability are important factors maintaining eusociality. However, in eusocial aphids, clone mixing between different colonies is reported to occur frequently, suggesting a lack of kin recognition. Studies investigating the clonal composition of eusocial aphid colonies have focused on the aphid generation on the primary host plant (gall generation). To test whether clone mixing also occurs in open colonies of eusocial aphids on their secondary host plants (open-colony generation), we carried out an amplified fragment length polymorphism analysis to investigate clonal composition within colonies of the eusocial aphid Ceratovacuna japonica. The results showed that clone mixing occurred frequently in open-colony generation

Discussion on Ohta et al., “Traveling bands in self-propelled soft particles”

A discussion on the contribution of Ohta and Yamanaka in this special issue, supplemented by new agent-based simulations of band collisions within the standard Vicsek-model

The spatial patterns of parasitism of eumenid wasps,Anterhynchium flavomarginatum andOrancistrocerus drewseni by the miltogrammine flyAmobia distorta

寄生率の空間的密度依存性は，同じ寄主－寄生者の組み合わせであれば，場所や世代が違っても基本的には同じパターンを示すという研究がこれまでなされてきた．本研究ではこの点について，世代によって寄生率の空間的パターンが異なっていった事例を示す．合わせて，異なる2種の寄主に対する寄生の空間的パターンが基本的には類似していたことも報告する．京都市の広範囲にわたる地域 (10km x 10km) において 1980 年から 1984 年にかけて野外調査を行った．この地域にパッチ状に分布する 2 種のドロバチ，オオフタオビドロバチ (Anterhynchium flavomorginatum) とオオカパフスジドロバチ (OrancistrocCTUS drewsent) に対するドロバチャドリニクバエ (Amobia distorta) の寄生率の空間的パターンをオオフタオビでは 4 世代，オオカバフでは7世代について調べた．寄生率の空間的密度依存性は，両寄主とも世代によってそのパターンが変化した．平均寄生率が低い世代においては，寄主密度の高いパッチほど寄生率も高くなった．一方，平均寄生率が高い世代においては，寄生率はパッチ当たりの寄主密度の高低にかかわらずほぼ一定であった．これらの傾向は両寄主ともにみられ，寄生率の基本的な空間的パターンは 2 種の寄主間で類似していた．代によって寄生の空間的パターンが違っていた理由を理解するために，ニクバエ成虫がパッチ閣でどのように空間分布しているかを，平均寄生率が低い世代について調べた．エクパエが少なくともl頭発見される確率は，寄主密度の高いノミッチほど高く，寄主の多いパッチにニクバエが集まってくることがわかった，しかし， IWAO (1968)の m-m 法で解析するとニクバエ成虫は空間的に正の二項分布をしており，互いにある程度以上こみあわないようにパッチを選んで、いることがわかった．パッチ当たり最大収容数は 4.05 頭と推定された．平均寄生率の高い世代においては，寄主を探索するニクバエの個体数が多いため，寄主密度の高いパッチでニクバエ同士の相互干渉が頻繁におこると考えられる．この干渉を避けるためにニクバエが寄主密度の低いパッチへ分散することによって，寄生率がどのパッチでも同じレベルになったと結論づけた