Microhabitat segregation of two coexisting tadpole species on Emei Mountain

Understanding mechanisms determining the coexistence between different species is one of the key issues in community ecology and biodiversity conservation. Microhabitat segregation is a way for species to coexist, which reflects the specific habitat selection of coexisting species in a finer spatial scale. Despite quantitative studies have been conducted to investigate the microhabitat segregation of coexisting species, this type of studies was not often performed on tadpoles. In this study, we assessed the habitat selection of two coexisting tadpoles (Quasipaa boulengeri and Leptobrachium boringii) in a stream on Emei Mountain, China. Our results demonstrated that L. boringii and Q. boulengeri tadpoles occupied different microhabitats. Specifically, Q. boulengeri tadpoles preferred deep, narrow, and weak acid stream segments with slow current velocity and low value of conductivity, while L. boringii tadpoles tended to occur in a wide, shallow water bodies with relatively higher pH, conductivity, and current velocity. Overall, our study supported the Hutchinson’s niche concept, showing that at least one dimension of niche differentiation (i.e., microhabitat) occurred between coexisting tadpole species.

Seascape ecological view as a new insight of benthic foraminiferal community

<p>Foraminifers secrete various chemicals for chamber walls. They are calcium carbonates such as calcite, aragonite, Mg-calcite, organic compounds for agglutinated chambers and/or organic cemented test walls.  Foraminiferal test walls basically form according to genetic information.  However, same test group is tended to gather at specific microenvironments.  For instance, turf shaped algal microhabitat such as coralline algae at rocky shore is composed of both frond and thallus parts as microhabitat.  Frond part is open space where fresh seawater moves inbetween one frond and the other.  <em>Elphidium crispum</em>, <em>Pararotalia nipponica</em> and <em>Patellina corrugate</em> and other calcareous foraminifers dwell at frond surface.  In contrast, thallus part is muddy and high concentration of organic matters.  The thallus part shows less oxygenated than frondal part as the space is close.  Microbial cascades are developed at thallus part.  Minor elements such as Mg or Sr are relatively high in sediment.  Soft-shelled forms such as <em>Allogromia</em>, gromiid, agglutinated forms and miliolids groups with high magnesian calcite tests flourish at the thallus part.</p><p>Microhabitat segregation and microenvironmental differences may cause similar biomineralization of benthic foraminiferal tests.  I would like to stress that micro-seascape should be important to characterize benthic foraminiferal assemblages.</p>

Behavioural aspects of microhabitat segregation of different age stages in the wetland land snail Vertigo moulinsiana (Eupulmonata: Vertiginidae) in the laboratory

ABSTRACT This laboratory study investigated behavioural differences between adults and juveniles of the wetland land snail species Vertigo moulinsiana with respect to temperature and humidity. Juveniles of V. moulinsiana, for example, tend to remain within the shaded, humid and cool layer of the litter, while adults usually climb above wet vegetation to a height of over 2 m. Adults are thus exposed to greater variation in temperature and humidity than juveniles. My experiments showed that adults of V. moulinsiana remain active longer than juveniles when subject to high temperature (36 °C) and low relative humidity (RH 30%). Conversely, juveniles stay active longer than adults in high humidity (22 °C, RH 100%). A short period of starvation lengthened the time needed for the juveniles to become active after dormancy, possibly indicating a different response between adults and juveniles to lack of nutritional reserves. These behavioural differences to food availability and the risk of water loss correspond to the microhabitat differences observed between adults and juveniles in the wild.

Microhabitat segregation among three co-existing species of grasshoppers on a rural meadow near Seoul, South Korea

Microhabitat segregation among grasshopper species in Asia has not been well studied. We determined the differences in the use of substrates by three common North East Asian grasshopper species co-existing on a natural meadow near Seoul, South Korea. While many Oedaleusinfernalis individuals were found on the ground, Acridacinerea and Atractomorphalata were usually observed on plants. Acridacinerea was mostly observed on the grass Zoysiajaponica (Poaceae) and Atractomorphalata was mostly found on plants from the family Asteraceae. This is the first study to provide quantitative information about microhabitat differences among some common grasshoppers in rural habitats of continental North East Asia. Future studies should focus on determining the mechanisms that produce such ecological segregation.

Parasite-mediated microhabitat segregation between congeneric hosts

Parasite-mediated competition can shape community structure and host distribution. If two species compete for resources, parasites may indirectly change the outcome of competition. We tested the role of a trematode parasite in mediating microhabitat use by congeneric isopods Austridotea annectens and Austridotea lacustris . Although both isopods share resources, they rarely co-occur in the same discrete microhabitats. We set up mesocosms with and without competition and/or parasites to examine the role of parasites in host distribution and habitat segregation. Austridotea annectens showed a clear preference for one microhabitat type regardless of competition or parasitic infection. By contrast, A. lacustris showed little habitat selection in the absence of competition, but favoured sandy habitats in the presence of uninfected A. annectens and rocky habitats when competing with infected A. annectens . Our results suggest that parasites in one species affect the distribution of another species, and mediate competition between these species. We demonstrated the impacts of a parasite on the microhabitat use of its host's competitor. This also represents an example of a super-extended phenotype, where a parasite affects the phenotype of a non-host.

Seven new species of Tortanus (Atortus) (Copepoda, Calanoida, Tortanidae) from North Sulawesi, Indonesia

Seven new species of the planktonic copepod genus and subgenus Tortanus (Atortus) are described from North Sulawesi, Indonesia. Four of these species, T. (A.) indonesiensis, T. (A.) omorii, T. (A.) processus and T. (A.) lukmani, belong to the brevipes species complex sensu Ohtsuka & Kimoto (1989). Two species, T. (A.) sulawesiensis and T. (A.) manadoensis, can be placed in the recticauda species complex. The seventh species, however, T. (A.) bilobus, belongs to neither group, which will necessitate a revision of the current morphology-based grouping with the aid of a genetically-based phylogeny. The co-occurrence of multiple closely-related congeners in a relatively small area suggests possible microhabitat segregation among these species.