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Tamalia [Macrosiphini]Tamalia have the antennal tubercles and the median frontal tubercle absent. The antennae are 6-segmented, with transverse rows of minute spicules, and in the alates narrow transverse secondary rhinaria. The terminal process is short, less than 0.5 times the base of antennal segment VI. In the alate the forewing has the media vein twice branched. The first tarsal segment has 2 dorsal and 7 ventral hairs. The siphunculi are essentially poriform. The cauda is rounded, broader than long and the anal plate is entire. There are 4-5 species of Tamalia, all found in North America. Tamalia are monoecious holocyclic on manzanitas (Arctostaphylos, Ericaceae). They live concealed in galls on leaves. Both the ovipara and the male are alate. The ovipara lays an unusually large number of eggs. Tamalia coweni (Manzanita leafgall aphid) Canada, Western USA, MexicoFeeding by the aphid Tamalia coweni on manzanita (Arctostaphylos) leaves induces red or reddish-green elongate to pod-shaped galls (see first picture below) within which the aphids feed and develop. Adult apterae of Tamalia coweni (see second picture below) are dull dirty yellow to dark green or blackish, with variably-developed dark sclerotic cross-bands on the tergites and sternites (cf. Tamalia inquilinus adult apterae, which have the tergum entirely sclerotic and coloured dusky dark). The head, appendages and genital plate are dark. The antennae are usually 4-segmented (cf. Tamalia inquilinus, which has 5 antennal segments). The apical rostral segment (RIV+V) is 0.9-1.5 times the length of the second hind tarsal segment (HT II) and bears 4-13 accessory hairs (cf. Tamalia dicksoni and Tamalia milleri, which have RIV+V 1.8-2.1 times as long as HT II, with 18-39 accessory hairs). The dorsal body surface is ornamented with numerous small spicules. Siphunculi are present as pores on small flattened cones. The body length of adult apterae is 1.25-1.5 mm. Immature Tamalia coweni are greenish without any cross bands.
First picture above copyright John Rusk, second picture above copyright James Bailey, The alate Tamalia coweni (see PMH Handbook) has a dusky abdomen with transverse spino-pleural sclerotic cross bands and a light brown pterostigma. Tamalia coweni feeds on manzanitas and bearberries (Arctostaphylos spp.) inducing characteristic galls. Tamalia species have a unique biology amongst galling aphids including an alate ovipara and no host alternation: all other galling-aphid taxa are host-alternating or secondarily monophagous (Miller, 2005 ). The overwintering eggs hatch in late winter or spring and the emerging fundatrices move to the leaves where they feed. Both the fundatrix and third generation aphids (referred to as foundresses) of Tamalia coweni induce galls. Both fundatrices and foundresses are wingless and generally remain within the gall, alternating with winged individuals, which disperse from the galls. In the final, sexual generation in fall, both males and oviparae are winged and disperse before mating. The eggs are laid on bark at the base of the host plant. The manzanita leafgall aphid is found in western North America, across boreal Canada to Ontario, and south through western USA to Mexico.
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ew.jpg "Tamalia coweni (manzanita leaf gall aphid) galls on Arctostaphylos parryana at Regional Parks Botanic Garden, Tilden Regional Park, Berkeley, California, USA; John Rusk")
