The Canary Islands together with the Azores, Madeira, the Salvajes Islands and Capoverde form a biogeographical region known as Macaronesia. The archipelago of the Canary Islands lies in the Atlantic Ocean, 100 kilometres west of the African coast. It consists of seven large islands and four smaller ones. Beccy and I visited El Hierro and La Gomera, two islands belonging to the western group of Canary Islands. Several habitats or ecosystems can be recognised in the Canary Islands, each with its own typical plants species and insects accompanying them. From an entomological point of view the most interesting habitats are the dry belt (Figure 1), the laurel-leaf woodland (Figures 2), pinewoods (Figure 3) and the highlands (absent from El Hierro and La Gomera).
One of the most beautiful localities in El Hierro was situated near to the village of Isora (Figure 4). In this locality we found Deroplia hesperus (Wollaston, 1863), a species only known from El Hierro. Adults of this beetle were sitting on Rumex lunaria L. or Artemisia thuscula Cav. at night, or could be found hiding in old pupal cells during the day (Figure 5). Larvae of this species were found in dead twigs of the above mentioned hosts.
Another species endemic to El Hierro, Deroplia costigera (Demelt, 1982), was found here on Kleinia neriifolia Haw. Adults of this beetle sit on living plants at night or hide in dead stalks and branches of the host during the day. Besides these two species Deroplia annulicornis (Brullé, 1838), a species found in several other islands within the archipelago, was very frequent here. Adults were found sitting on terminal buds and living or dead twigs of Ficus carica L. or on Kleinia neriifolia Haw. The western coast of the island turned out to be very interesting as well. In a place called Punta de la Dehesa we found another species endemic to El Hierro, Deroplia schurmanni Sama, 1996. The species develops in dead tissues (Figure 6) of various Euphorbia species such as Euphorbia regis-jubae W. & B. or Euphorbia balsamifera Ait. In Euphorbia regis-jubae W. & B. larvae of Deroplia schurmanni Sama, 1996 were accompanied by Lepromoris gibba (Brullé, 1838), a species found in all of the Canary Islands. The west facing slopes of El Hierro are undoubtedly the most beautiful part of the island. Here, extensive areas of intact habitat support a number of juniper trees (Figures 7a & 7b). Delagrangeus (Gertius) schurmanni Sama, 1985 is associated with this tree and indeed we managed to find old larval galleries in dead terminal twigs. No larvae however.
Charco Manso in the very north of the island is another very nice place (Figure 8) worth mentioning. Here in a dry habitat with Euphorbia balsamifera Ait. and some Euphorbia regis-jubae W. & B. in higher altitudes Deroplia schurmanni Sama, 1996 and Lepromoris gibba (Brullé, 1838) were recorded again. Deroplia annulicornis (Brullé, 1838) was common in the north and adults were found in dead stalks of Kleinia neriifolia Haw.
From El Hierro's airport in Valverde we flew to Tenerife and took a ferry to our next destination, the island of La Gomera. We stayed in a small village La Vizcaína in Valle Gran Rey (Figure 9). This place turned out to be an excellent locality for Deroplia gomerae Sama, 1996, a species only known from this island. Adults were recorded at night on their hosts and larvae were found in dead tissues (tiny twigs usually). The beetle was frequent and very polyphagous and could be found in Argyranthemum sp., Foeniculum vulgare Mill., Artemisia thuscula Cav., Amygdalus sp. and Ficus carica L. Deroplia albida (Brullé, 1838) was found in dead stalks of Euphorbia regis-jubae W. & B. in this locality as well (Figure 10).
In Alojera (Figure 11) and Vallehermoso situated in the north-west of the island we discovered several places with abundant Juniperus turbinata Guss. ssp. canariensis (Guy.). In recently dead branches of this tree we found adults and some pupae and larvae of Delagrangeus (Gertius) schurmanni Sama, 1985. Deroplia albida (Brullé, 1838) was recorded from dead stalks of Euphorbia aphyla Brouss. Ex Willd. in this locality as well.
Blabinotus spinicollis Wollaston, 1854 is another interesting species present to this island. We discovered this beetle in dead branches of Laurus azorica (Seub.) Franco just outside of Hermigua. The species does not seem to tolerate the high moisture content of branches lying on the ground. The insect prefers branches within the canopy or even better, new shoots of the host growing in shady positions. Only occasionally when such branches break, the insects can be found in highly moist wood. Some adults hatch in December and appear later in February but the main part of the population occurs in August.
MH & MR © August 1, 2006
|
