Hymenoptera Highlights II

by Ian Hamer

Several trips into the mountains and desert have been made during the past few months, but because of the generally cold and windy weather the more interesting species of bees and wasps have not been venturing forth to be collected.

On a very damp Christmas Day in Hatta we managed to reach the Wadi Fayd (see map in Bulletin 15). The track remains very rough in places after the rains of Spring 1982, with steep and loose inclines and is definitely not recommended for saloon cars past the first couple of wadis.

Although it was too early and cool for most vegetation to benefit from the showers of last November/December, the Wadi Fayd was, due to its current inaccessibility, almost free of the usual rubbish that popular picnic sites seem to attract. The water level in the rock pools and other areas of flowing water was substantially higher than it was twelve months ago and aquatic life was obviously thriving. The usual fish and toads were present in abundance, and a brown snake was nearly trodden upon in a plantation; unfortunately it slithered away quickly, making identification impossible. With rain falling all around it was with an extreme feeling of relief when the last wadi was left behind and open higher ground was reached.

Only a few wasps were collected during this expedition and it was generally a disappointing visit from this aspect although the Calotropis bushes on the Shwayb - Madam road, as well as the grounds of the Hatta Fort Hotel, yielded one or two new species. At Shwayb we also observed a lizard enjoying a small scorpion for lunch.

A visit to Al Ain over the New Year provided several species although only one or two are new to the Group's collection. A day trip to Abool (near Mahdah, beyond Buraimi) gave us a pleasant ramble up a wadi with flowing water and reasonable cover of vegetation. An old fort contained several abandoned wasp nests, some of which were collected and are now in the Workroom showcase. No signs of current habitation or building were evident. However, only a small number of insects were collected from this area and the most profitable sites were in the grounds of the Intercontinental Hotel and Hili Gardens.

A rather cold and damp journey to the Liwa previously likewise provided very little in the way of insect life. As the sand was very firm due to recent rains we ventured past Al Mariah through the ADCO camp and Shah and thence towards the Saudi border. Although the drive gave a taste of desert scenery at progression, nothing of interest was spotted apart from the usual 'traces', lizards and one hare.

The lack of collecting success has given the opportunity for a few notes on identification to be included. The most difficult exercise is to try and identify a bee or wasp after a single cursory glance as it flies from flower to flower. Insects are accomplished mimics and it is extremely easy to make a fundamental error. Even in the net or bottle the task is not much easier and the only sure way is to take every specimen home for identification under a microscope.

The following notes have been simplified in an attempt to provide a layman's key to determining the Superfamilies of the Aculeata (bees and wasps). As such it is by no means scientifically accurate and there are many exceptions. However, it will provide a useful aid for the determination of most common specimens that are likely to be collected or seen in the U.A.E.

All Hymenoptera display the following:

(i) three different body sections - head, thorax and abdomen.
(ii) two pairs of wings. The forewings are larger than the hindwings, and a series of tiny hooks joins the wings in flight (this obviously does not apply to the flightless females of some species of ants etc.).
(iii) mandibles are always present.

The Hymenoptera Order is divided into two sub-orders as follows:

(i) Symphyta (sawflies and wood wasps), which have no 'waist' between the thorax and abdomen.
(ii) Apocrita (including inter alia bees, wasps, ants and Parasitica), which have a very narrow 'waist between thorax and abdomen although this is not sometimes visible to the naked eye.

The further division of the Apocrita sub-order becomes difficult and a much more detailed examination is required, often utilising a lens or microscope. For simplicity only the Aculeata (stinging insects) have been considered further, the Parasitica being completely ignored.

Most of the Aculeata have 12 or 13 antennal segments (12 in the female, 13 in the male). Generally they also have 6 visible abdominal segments in the female and 7 in the male, though there are exceptions. Wing venation is usually complex and the hind wings often have an anal lobe.

The further split into Superfamilies now becomes more straightforward but the following gives a general rule rather than a rigidly accurate index.

All of the following Superfamilies have at least one closed cell in the hind wing:

(i) Vespoidea (true wasps) - Pronotum reaches back to tegulae and overlaps the tegulae at an acute angle. Front wings fold longitudinally at rest and eyes are usually emarginate.
(ii) Sphecoidea (fossorial or digging wasps) - Pronotum does not reach back to the tegulae, front wings do not usually fold at rest and eyes are not usually emarginate. Hind tarsi is slender and cylindrical and is never covered with brush-like hair.
(iii) Apoidea (bees) - Pronotum does not reach back to the tegulae, front wings do not fold at rest and eyes are not usually emarginate. Hind tarsi is broad and flattened and often very hairy.
(iv) Pompiloidea (spider hunting wasps) - Pronotum reaches back to tegulae. Front wings are not folded at rest and eyes are not usually emarginate. Legs are long, especially the hind femur, and the tibia and tarsus are spined or toothed.
(v) Scolioidea - Although these are parasites this group is included in the Aculeata. The pronotum reaches back to the tegulae, front wings are not folded at rest and eyes are usually emarginate. Legs are usually short and stout and frequently hairy.

Sessile abdomen of Sawfly (T = Thorax; A = Abdomen; C1, 2, 3 = Coxa)
Petiolate abdomen of a wasp (ditto)
Pronotum of a Sphecid
Pronotum of a Pompilid
Lateral pronotal angle of a Vespid (NI = Pronotum; TG = Tegula)
Ditto of a Pompilid
Typical hymenopterous leg (C = Coxa; F = Femur; TB = Tibia; TR = Trochanter; TS = Tarsus)
Hind leg of a Bee
Hind leg of a Wasp
Typical Head (M = Mandible; E1 = non-emarginate eye; E2 = emarginate eye)

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