Dinas (Microspina), Skuhrovec & Batelka, 2014

Skuhrovec, JiĜí & Batelka, Jan, 2014, Taxonomy of the Cape Verde endemic weevil genus Dinas (Coleoptera: Curculionidae: Entiminae). Part I: Description of a new subgenus, and two new species from São Nicolau Island, Acta Entomologica Musei Nationalis Pragae 54 (1), pp. 315-336 : 332-333

Biology of Dinas

Available data indicate that the biology of both Dinas subgenera are quite different. Since WOLLASTON (1867), members of the Microspina subgen. nov. were considered to be associated mainly with the stands of Euphorbia tuckeyana Steud. , although the type series of D. obsita was collected on flowers of endemic Tornabenea insularis (Parl.) Parl. Dinas sitonaeformis was reported by WOLLASTON (1867) from Malva parviflora Linnaeus (an introduced species of Malvaceae ; ARECHAVALETA et al. 2005) and D. micans Roudier, 1957 was collected on one occasion, in more specimens on the introduced Cajanus cajan (L.) Millsp. ( Fabaceae ) (specimens examined in SMNS). Dinas afonsoi sp. nov. from Tope de Chuva was collected exclusively on flowers of Euphorbia tuckeyana ( Figs 6 , 7A–C ), while D. sitonaeformis from Chã de Caldeira was collected mainly from flowers of Periploca laevigata chevalieri (Browicz) G. Kunkel (Asclepiadaceae) ( Figs 7A–B ), but several specimens of this species were collected also on flowers of the nearby growing Euphorbia tuckeyana . Both Euphorbia and Periploca species are shrubs endemic to the archipelago – which are able to survive under a great variety of conditions ( GOMES et al. 1999). Specimens of D. afonsoi sp. nov. and D. sitonaeformis were observed eating flowers and pollen grains of Euphorbia .

On the contrary, adults of the nominate subgenus apparently have a different biology. Both species of Dinas s. str. were found only under stones on the extreme summits of Monte Verde ( São Vicente) ( WOLLASTON 1867) and Tope de Chuva (São Nicolau). Both summits simultaneously represent the highest point of the particular island/former island. This similarity in the habitats of both species is most probably not coincidental. A similar type of distribution is found in the tenebrionid genus Melanocoma , which is assumed to be the most relictual tenebrionid beetle element in Cape Verde ( GEISTHARDT 2003). Three species of this genus are restricted to the summits of three islands of the Southern Chain. It is supposed that all three species are surviving in these high-altitude places following a period of more humid climate, when they were also present in lower altitudes, and were able to spread to other islands of the archipelago ( GEISTHARDT 2003). Adults of Dinas s. str. moreover correspond well to some ground-dwelling Entiminae (e.g., Trachyphloeini ) in antennal morphology: the scape is shorter than the scrobe, and at the same time it is as long as or shorter than the funicle. This indicates that, unlike the species of Microspina subgen. nov., the species of Dinas s.str. do not visit the blossoms of flowering plants. Moreover, both species of Dinas s.str. were collected syntopically with species of Microspina subgen. nov. which also supports the idea of differentiation in habitat preference in these two subgenera.

Figures

Fig. 6. Habitat of Dinas species: Summit of Tope de Chuva, São Nicolau – the type locality of Dinas (s. str.) strakai sp. nov. and Dinas (Microspina) afonsoi sp. nov.

Fig. 7. Habitats and biology of Dinas species: A–C – Dinas (Microspina) afonsoi sp. nov. on flowers of Euphorbia tuckeyana; D – Dinas sitonaeformis Wollaston, 1867 on twig of Periploca laevigata chevalieri in Chã de Caldeira; E – grassy slopes of Chã de Caldeira, São Nicolau with scattered Periploca laevigata chevalieri – locality of Dinas sitonaeformis. (Photos by Jakub Straka).