Nana Gratiashvili

The Caucaso-Anatolian slave-making ant Myrmoxenus tamarae (Arnoldi, 1968) and its more widely distributed congener Myrmoxenus ravouxi (André, 1896): a multidisciplinary comparison (Hymenoptera: Formicidae)

A small minority of the presently recognized ∼12,500 species of ants are slave-makers, which permanently depend on the help of “slave workers,” that is workers of other ant species, which they pillage as brood from their nests in well-organized slave raids. The genus Myrmoxenus is one of the most species-rich taxa of slave-making ants, but individual species are often not well-delimited. Here, we compare behavior, morphometry, and nuclear and mtDNA sequences between two taxa of Myrmoxenus: Myrmoxenus tamarae (Arnoldi, 1968), known only from its type locality in Georgia, and the wide-spread M. ravouxi (André, 1896) to determine if the former might simply represent a Caucasian variant of the latter. Workers of the two taxa differed clearly in locomotor activity and slightly also in morphometry, while genetic investigations with nuclear and mitochondrial genes revealed only a weak differentiation. Given that Myrmoxenus appears to be a genus with a relatively recent radiation, we suggest to conservatively keep the present taxonomic situation with M. ravouxi and M. tamarae as separate species. The latter would then include specimens from Eastern Turkey and probably also Ukraine. Further studies, in particular in Greece and Turkey, might help to clarify the status of these endangered ants.

Note on Wahlgreniella nervata (Gillette, 1908) (Hemiptera: Aphididae): a new pest of Damask rose in Turkey

Alate viviparous females of Wahlgreniella nervata (Gillette) were found on a Damask rose (Rosa damascena Mill.) plantation in Isparta Province, Turkey. The aphid is recorded for the first time from Turkey. Besides, Damask rose is a new host for this species. Brief information about this aphid including a key to the alate females of aphid species known to infest Damask rose in Turkey is provided.

Body size but not colony size increases with altitude in the holarctic ant, Leptothorax acervorum

1. Bergmanns rule states that organisms inhabiting colder environments show an increase in body size or mass in comparison to their conspecifics living in warmer climates. Although originally proposed for homoeothermic vertebrates, this rule was later extended to ectotherms. In social insects, only a few studies have tested this rule and the results were ambiguous. Here, ‘body size’ can be considered at two different levels (the size of the individual workers or the size of the colony).

High skew in the Caucasus: functional monogyny in the ant Leptothorax scamni

Animal societies vary considerably concerning how reproductive rights are partitioned among individual group members (“reproductive skew”). Nestmate queens of most polygynous species contribute more or less equally to the brood, but queens of a few species of the genus Leptothorax form dominance hierarchies in which only the top ranking queen lays eggs (“functional monogyny”). As predicted by optimal skew models, high skew appears to be associated with habitat patchiness. Here, we document functional monogyny in the Caucaso-Anatolian ant Leptothorax scamni (Ruzsky 1905). Similar to related species, young female sexuals mate on the ground near their natal nests and thereafter either disperse to found new colonies solitarily or in groups or return into their natal nest, where only one of several co-occurring queens reproduces. A phylogeny of Leptothorax species based on partial CO I sequences corroborates the view that functional monogyny has evolved convergently in several taxa of Leptothorax. It thus is a relatively labile trait that can rapidly adapt to habitat changes.

Description of fundatrices of Zelkovaphis caucasica (Hemiptera: Aphididae: Eriosomatinae) and its life cycle

Abstract Fundatrices of Zelkovaphis caucasica (Dzhibladze 1960) are described and illustrated. A key to the fundatrices of the genus Zelkovaphis species is given. A transfer experiment was carried out to establish the life cycle of Z. caucasica. In addition, the life cycle of this species was studied in field conditions. The secondary host plant was established as Carex capitata.

Description of oviparous females and alate males of Macrosiphum dzhibladzeae Barjadze, 2010 (Hemiptera: Aphididae) from Georgia

Summary The hitherto unknown oviparous females and alate males of M. dzhibladzeae Barjadze, 2010, living on Euphorbia macroceras Fish. & Mey. and Euphorbia sp. (Euphorbiaceae), are described from resort Bakhmaro (Chokhatauri district, Guria region, Western Georgia). The life cycle of this species is established. Apterous and alate viviparous females and oviparous females of M. dzhibladzeae are compared to the same morphs of morphologically similar M. meixneri Börner, 1950. A key is provided to Euphorbia-feeding Macrosiphum spp. based on males.