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Schlechtendalia [Fordini]Schlechtendalia are gall-forming aphids related to Melaphis. The antennal terminal process is very short, much less than 0.5 times the length of the base of the last antennal segment. The pterostigma of the forewing extends in a curve around the tip of the wing (cf. Melaphis which do not an elongate curved pterostigma). Siphunculi are absent. There are only two species in this genus, since two members of Schlechtendalia were moved to a separate genus, Meitanaphis. Both the current species of Schlechtendalia, as with Melaphis, host alternate between sumac (Rhus) and mosses. They are found in East & South-east Asia. Schlechtendalia chinensis ( Horned gall aphid) East & South-east AsiaFundatrices of Schlechtendalia chinensis induce horned galls on the Chinese sumac, Rhus chinensis. The galls are greenish-yellow or reddish green, densely covered with short, fine hairs, ovoid, becoming woody and irregular in shape with horn-like protrusions, from 1-6 cm long (see picture below). After several generations in the gall, emigrant alatae are produced in October and fly to found overwintering colonies on their secondary host, mosses such as Mnium and Plagiomnium.
Image above copyright Onidiras under a Creative Commons License.
The emigrant alatae (not pictured) can be readily identified. The antennae are 5-segmented. The antennal terminal process is short and thick, much less than 0.5 times the length of the base of the last antennal segment. Antennal segment III is longer than the base of antennal segment V (cf. Schlechtendalia peitan, which has antennal segment III shorter than the base of antennal segment V). The antennae bear strap-like, annular secondary rhinaria. Antennal segments II-V each have at least partial separation of the sensoriated surface into smaller units. The pterostigma of the forewing extends in a curve around the tip of the wing. There are no siphunculi. The body length of emigrant Schlechtendalia chinensis alatae is about 1.5 mm. Schlechtendalia chinensis is heteroecious (= host alternating) holocyclic, with an unusual one-year cycle. In early spring, aphid nymphs on the secondary host, mosses, develop into alate spring migrants, which are sexuparae. These sexuparae migrate to nearby primary hosts, Rhus chinensis trees, where they produce non-feeding sexuales in the bark crevices. After mating, each female lives for about 3 weeks and then produces a single fundatrix ovoviviparously. The young fundatrix crawls up the trunk to feed on the new leaves, where it initiates gall formation. The fundatrix feeds inside the gall and produces numerous offspring. After several generations in the gall, winged migrants are produced in autumn which fly to mosses, their overwintering host. It is assumed all of their nymphs mature to sexuparae in the next spring (no wingless adults have been recorded on moss) and these spring migrants return to the primary host and begin a new cycle. The galls that Schlechtendalia chinensis produces on the primary host, known as Chinese gall-nuts, have been collected for many years. They have been used in tanning leather, in the preparation of dyes and for medicinal purposes. The species is found in China, Japan, Korea, Taiwan and Malaysia.
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