ions dry into a cellophane-like lining. This allows the bees to nest in periodically flooded areas such as stream banks. There are over 2000species, all of them evidently solitary, though many nest in aggregations. Bees in this are highly varied in appearance and have few common features. One feature consistent to all colletid bees is that their tongue has a branched tip (Figure 59) . The two genera most frequently seen are Colletes and Hylaeus.
Two of the subfamilies, Euryglossinae and Hylaeinae, lack the external pollen-carrying apparatus (the scopa) that otherwise characterizes most bees, and instead carry the pollen in their crop (enlarged portion of the foregut). These groups, and in fact most genera in this family have liquid or semi-liquid pollen masses on which the larvae develop.
Colletid Bee. Image Courtesy of Michael Becker.
They can be found all over the world, but the most species live in South America and Australia. Over 50% of all bee species living in Australia belong to this family. Only the genera Colletes and Hylaeuscan be found in Europe, while in North America there are, in addition to these two, the genera Caupolicana, Eulonchopria, and Ptiloglossa.
Ants are among the most highly evolved of insects. The variety of lifestyles displayed by ants is amazing--perhaps because so many of their social behaviors seemingly parallel our own.
All living ant species have a caste system. The main castes consist of kings, queens and workers. The kings are winged reproductive males that contribute absolutely nothing to the labor of the colony. The winged females swarm with the males, similarly to the behavior previously discussed with termites. Eventually they will become the queens of new colonies. During the establishment of a new colony, the new queen initially performs all the work tasks; but once her first brood of worker larvae is reared to adulthood, her sole duty is to lay eggs. Unlike termites, ant colonies may have many queens, in some cases, hundreds.
Workers are sterile females and can be both the laborers and defenders of the colony. In most ant species there can be sub-castes of the workers, namely majors, media and minors. Relative head and overall body size distinguish subcastes. The majors are the largest of the three and possess a disproportionately large head and mandibles. The function of the soldiers is to protect the ant colonies. The media and minor workers are the most common individuals in an ant colony and perform the majority of the work duties. Minor worker ants also perform a variety of functions depending on the species of ant.
Ant Wars, Competition and Survival. Ants are amongst the most aggressive and war-like of all animals. If ants had a policy of life it could be summarized as restless aggression, territorial conquest, and total annihilation of neighboring colonies. These insects use any of a number of strategies and weapons to reach these ultimate goals. Chemical warfare is prevalent amongst many species including spraying a variety of toxic chemicals in order to repel, confuse, immobilize or even kill their rivals. The soldiers of many species readily assume a kamikaze role in order to “win skirmishes” between rival colonies. One of the most dramatic of these sacrifices is exhibited by a carpenter ant from SE Asia. These ants act as walking bombs. There is a huge internal gland that occupies much of their body that is filled with toxic chemicals. If one of these ants is hard pressed by a rival ant or predator it contract some large abdominal muscles that bursts open the abdomen violently (like a bomb) releasing the chemicals.
The availability or more significantly the limited availability of food frequently is important in colony survival. As a consequence rival colonies frequently develop strategies to maximize their collection of available food. There is a tiny fast moving ant in the deserts of Arizona that utilizes toxic secretions to intimidate and confuse much large honey ants (10 time their size) as they steal food from the larger ant colonies. In addition these tiny ants 