Dysaphis indica Chakrabarti & Medda 1993, new status

Abstract

<i>Dysaphis indica</i> Chakrabarti & Medda, 1993, new status <p> This aphid has previously been treated as a subspecies of <i>Dysaphis pavlovskiana</i> Narzikulov, 1957. Chakrabarti and Medda (1993) described 53 apterous viviparous females collected from <i>Sorbus</i> in India (Uttar Pradesh, Garhwal Hills) as specimens of new subspecies— <i>Dysaphis pavlovskiana indica</i>. They noted that the new subspecies differs from the nominative taxon mainly in the lack of spines on the head, the greater length of the ultimate segment of rostrum, the slightly longer siphunculus and the fact that all the setae on the antennae were thin and pointed unlike those of the nominotypical subspecies, which has most of the setae on the antennae blunt or slightly capitate. Actually there is no description of the apterous vivipara in their paper, which only gives the differences listed above and measurements of several characters of the holotype. The authors also suggested that the seven alate and two apterous viviparous females and 30 nymphs which they collected on 16 September 1982 from <i>Saussurea piptathera</i> Edgew. (cited as <i>Saussurea pipethera</i> in their paper) in Uttar Pradesh (Garhwal Hills), as well as one alate female which they caught on 17 September 1982 on <i>Rhamnus dahurica</i> Pall. in Garhwal Hills refer to this subspecies. According to the authors the aphid was accidentally on <i>Rhamnus dahurica</i>. They also suggested that the alatae collected on <i>Saussurea</i> are gynoparae which should migrate to <i>Sorbus</i>. Indeed, judging by the description of alatae and apterous viviparous females from <i>Saussurea piptathera</i> given in the article and by the comparison of aphids from <i>Sorbus</i> and aphids from <i>Saussurea</i> made by the authors, these individuals all belong to one taxon.</p> <p> Hitherto <i>Dysaphis pavlovskiana</i>, sensu stricto was known from Eastern and Western Siberia, Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan and Pakistan (Narzikulov 1957; Ivanovskaya, 1977; Gabrid, 1989; Kadyrbekov, 1990; Naumann-Etienne & Remaudière, 1995; Stekolshchikov & Shaposhnikov, 1998; Holman, 2009). Slides have now been studied of aphids collected by G. Remaudière on 17 June 1966 from <i>Sorbus graeca</i> (Lindl.) Fritsch & Rech. in Turkey (Konya, Ereğli) at an altitude of 2000 m above sea level and stored in the aphid collection of Muséum national d'Histoire naturelle.</p> <p> This sample contains four fundatrices, eight apterae and 34 alate viviparous females. These aphids are very similar to <i>D. pavlovskiana</i> housed in the Russian collections in all characters, differing from them only by the greater length of the ultimate segment of the rostrum and its relation to the length of 2nd segment of hind tarsus, as well as having more long setae on the body and appendages. However, if we consider the variation in these characters in different populations of <i>D. pavlovskiana</i> (Tabl. 1), we see that when going from north to south, not only the absolute length of the ultimate segment of the rostrum but its ratio to the length of 2nd segment of hind tarsus increases, and this phenomenon is more or less clearly expressed for all morphs for which it is possible to make a comparison. A similar, though less clearly expressed situation is observed with the length of setae. Individuals from Turkey are thus just an extreme variant on the line of these changes, conforming completely to this trend and undoubtedly belonging to the species <i>D. pavlovskiana</i>.</p> <p> The situation is different with <i>Dysaphis pavlovskiana indica</i> Chakrabarti & Medda, 1993. In <i>indica</i> the absolute length of the ultimate segment of the rostrum is greater than in <i>pavlovskiana</i> s.str., but the ratio of the length of the ultimate segment of the rostrum to the length of the second segment of hind tarsus does not differ (Table 1). In addition, <i>indica</i> differs from <i>pavlovskiana</i> in the following characters (apart from those listed in the original description): body length (<i>indica</i> longer), ratio of length of processus terminalis to length of base of last antennal segment (greater in <i>indica</i>, especially for the morph from <i>Saussurea</i>), longer cauda (at least for morph from secondary host), number of rhinaria on the segments of antenna of gynoparae (more in <i>indica</i>), and by some other characters (Table 2). Information about the length of setae of apterous females of <i>indica</i> from <i>Sorbus</i> is absent from the original description, but morphs of <i>indica</i> from the secondary host have longer setae than the respective morphs of <i>pavlovskiana</i>. However, as stated above, this character has no significant value in the taxonomy of this group. Apterous exules of <i>pavlovskiana</i> from <i>Plantago</i> are strongly sclerotized, with sclerotic bands from meso- or metathorax to VII abdominal tergite fused with marginal sclerites and forming a complete dorsal shield. Apterae of <i>indica</i> from <i>Saussurea</i> are almost unsclerotized, having only a sclerotized band on abdominal tergite VIII. The secondary host of <i>indica</i> is <i>Saussurea</i>, whereas <i>pavlovskiana</i> migrates from <i>Sorbus</i> to <i>Plantago</i> (Shaposhnikov, 1974; Stekolshchikov & Shaposhnikov, 1998). These significant differences between <i>indica</i> and <i>pavlovskiana</i> in morphology and, more importantly, in biology (a different secondary host) indicate that it as a separate species— <i>Dysaphis indica</i> Chakrabarti & Medda, 1993 <b>(new status).</b></p> <p> <i>D. indica</i> is undoubtedly very closely related to <i>D. pavlovskiana</i> and they have a common ancestor that may have migrated from <i>Sorbus</i> in the second and third generation to a more-or-less wide range of secondary hosts. This ancestor had a long ultimate segment of the rostrum, long thin setae, slightly swollen or unswollen siphunculi, and strongly sclerotized apterous viviparous females on <i>Sorbus</i> and on secondary hosts. After separation <i>D.indica</i> apparently remained in a relatively narrow area within the Himalayas, while <i>D. pavlovskiana</i> became widespread in Eurasia—from Turkey to Eastern Siberia. As already pointed out (Stekolshchikov & Shaposhnikov, 1998), the spread of <i>D. pavlovskiana</i> from south to north was accompanied by some changes in its morphology and, more importantly, in its biology; both emigrants and apterous viviparous females are among the offspring of the fundatrix in populations of Tajikistan and Turkey (in Tajikistan apterae are found on <i>Sorbus</i> until the 5th generation), but there are no apterae on Sorbus in the Kazakhstan and East Siberian populations, the fundatrix producing only alatae females—emigrants.</p>Published as part of <i>Stekolshchikov, Andrey V., 2014, Taxonomic notes on some species and subspecies of aphids (Hemiptera: Aphididae), pp. 563-570 in Zootaxa 3760 (4)</i> on pages 563-565, DOI: 10.11646/zootaxa.3760.4.5, <a href="http://zenodo.org/record/224483">http://zenodo.org/record/224483</a&gt