Teleutotje hat geschrieben:With my previous topic. Read this in a dayly newspaper "Metro" on mo. 28 january 2019, p. 8, "mustread":
Abstract
Rhopalomastix is a myrmicine ant distributed throughout tropical parts of Asia, with almost nothing known about its biology. Its closest relative Melissotarsus in Africa is the only ant genus known to live with diaspidid scale insects inside their nests, and to rely on these for food. Twelve colonies of four species of Rhopalomastix were sampled from seven tree genera in Singapore. Ants chewed tunnels under live bark, and these were occupied by many diaspidids belonging to five genera; at least two species are known to also live freely on the outside of trees. Inside ant nests, only a few diaspidids secreted their trademark shields. The association with the pupillarial Fiorinia is unexpected, since they have fewer secretions that can be used as food by the ants. Rhopalomastix and Melissotarsus workers share several morphological adaptations, including powerful mandibles and silk glands, but while the legs of Melissotarsus are modified for traction during tunnelling, those of Rhopalomastix are not. Consequently, Rhopalomastix workers are able to walk outside their tunnels, but they behaved timidly except in R. murphyi. Silk was used to repair damaged tunnels, and the spinning behaviour resembled that of Melissotarsus. Host trees do not gain protection from the ants against leaf herbivores, so they apparently get no benefits from this mutualism. We discuss the likely economic impact of this parasitic lifestyle, especially on fruit trees.
--Abstract:
Many ant species construct nests and during the process considerably influence the environment such as by changing soil structure and creating new habitat for other species. However, other ant species dwell in ready-for-use cavities. Ants of the genus Temnothorax inhabit small cavities such as acorns and under rocks, but under natural conditions, good nest sites are limited resources. During field and laboratory experiments, I studied how the acorn ant Temnothorax crassispinus (Karawajew, 1926) modifies nesting sites. Temnothorax crassispinus is a forest species, which typically lives in cavities in fallen twigs and acorns; colonies usually number from a few dozen to about 200 workers. Although it is known that they prefer narrow entrances, in a field experiment, a similar proportion of artificial nest sites with narrower and wider entrances were inhabited, and most colonies decreased entrance sizes. Similarly, in laboratory experiments, colonies decreased entrance sizes. Colonies used more sand grains when sand was placed closer to the nest entrance than when it was farther; however, I found no relationship between the number of grains of sand used for such modifications and colony size, and the presence of other colonies in the same Petri dishes did not affect entrance-size reduction. Other experiments showed that the ants can enlarge the nest cavity, but this depends on the material filling the cavity, and that the ants are able to dig nest chambers just in soil. Thus, acorn ants can modify and create nest sites, and may thus also modify the environment.
Cardiocondyla zeichnet sich ja durch einige Besonderheiten aus, Männchen-Polymorphismus mit geflügelten, „normal“ erscheinenden, neben arbeiterinähnlichen, flügellosen und mit Dolchmandibeln ausgestatteten Formen. Solche „ergatoiden“ Männchen hatte man schon früher als Sozialparasiten beschrieben, sogar neue Gattungen für sie aufgestellt (Emeryia und Xenometra), die aber nach Aufklärung dieser Irrtümer mit der Gattung Cardiocondyla synonymisiert wurden.„The modification of the mandibles, clypeal structure and antennal funiculi suggest that this species is an inquiline. Based on it close resemblance, Cardiocondyla shuckardi may be the host of zoserka.“ - B. Bolton 1982.
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