Tuesday, March 28, 2017

Nature's Architects

The baya weaver (Ploceus philippinus)
The baya weaver (Ploceus philippinus) is a weaverbird found across the Indian Subcontinent and Southeast Asia. Flocks of these birds are found in grasslands, cultivated areas, scrub and secondary growth and they are best known for their hanging retort shaped nests woven from leaves. These nest colonies are usually found on thorny trees or palm fronds and the nests are often built near water or hanging over water where predators cannot reach easily. They are widespread and common within their range but are prone to local, seasonal movements mainly in response to rain and food availability.

Among the population variations, three subspecies are recognized. The nominate race philippinus is found through much of mainland India while burmanicus is found eastwards into Southeast Asia. The population in southwest India is darker above and referred to as subspecies travancoreensis

The Harvest Mouse

Harvest Mice tip the scales at barely eight grams. So these tiny creatures have no troubles climbing up even the slenderest corn stalks in order to build their cosy, spherical nests, which they construct from blades of grass at a height of up to one meter.  These clever little mice build their summer residence on stilts in the middle of fields and meadows so that hey and their young never have to go too far to find their next meal. 

Termite Mounds 
Termite Mounds or just mound builders are a group of termite species that live in mounds. This group of termites live in Africa, Australia and South America. The mounds sometimes have a diameter of 30 metres. Most of the mounds are found in well drained areas. Termite mounds usually out live the colonies themselves. If the inner tunnels of the nest are exposed it is usually dead, however, sometimes other colonies occupy a mound after the death of the original builders. The new colonizers may be of the same or a different species.
The structure of the mounds can be very complicated. Inside the mound is an extensive system of tunnels and conduits that serves as a ventilation system for the underground nest. In order to get good ventilation, the termites will construct several shafts leading down to the cellar located beneath the nest. The mound is built above the subterranean nest. The nest itself is a spheroidal structure consisting of numerous gallery chambers. They come in a wide variety of shapes and sizes. Some, like Odontotermes termites build open chimneys or vent holes into their mounds, while others build completely enclosed mounds like Macrotermes. The Amitermes (Magnetic termites) mounds are created tall, thin, wedge-shaped, usually oriented north-south.
Bowerbirds
Bowerbirds make up the bird family Ptilonorhynchidae. They are renowned for their unique courtship behaviour, where males build a structure and decorate it with sticks and brightly coloured objects in an attempt to attract a mate. The family has 20 species in eight genera. These are medium to large-sized passerines, ranging from the golden bowerbird at 22 centimetres (8.7 in) and 70 grams (2.5 oz) to the great bowerbird at 40 centimetres (16 in) and 230 grams (8.1 oz). Their diet consists mainly of fruit but may also include insects (especially for nestlings), flowers, nectar and leaves in some species. The satin and spotted bowerbirds are sometimes considered agricultural pests due to their habit of feeding on introduced fruit and vegetable crops and have occasionally been killed by affected orchardists.
The bowerbirds have an Austro-Papuan distribution, with ten species endemic to New Guinea, eight endemic to Australia, and two found in both. Although their distribution is centered on the tropical regions of New Guinea and northern Australia, some species extend into central, western, and southeastern Australia. They occupy a range of different habitats, including rainforest, eucalyptus and acacia forest, and shrublands.
Weaver ants
Weaver ants or green ants (genus Oecophylla) are eusocial insects of the family Formicidae (order Hymenoptera). Weaver ants are obligately arboreal and are known for their unique nest building behaviour where workers construct nests by weaving together leaves using larval silk. Colonies can be extremely large consisting of more than a hundred nests spanning numerous trees and contain more than half a million workers. Like many other ant species, weaver ants prey on small insects and supplement their diet with carbohydrate-rich honeydew excreted by small insects (Hemiptera). Oecophylla workers exhibit a clear bimodal size distribution, with almost no overlap between the size of the minor and major workers. The major workers are approximately 8–10 mm (0.31–0.39 in) in length and the minors approximately half the length of the majors. There is a division of labour associated with the size difference between workers. Major workers forage, defend, maintain, and expand the colony whereas minor workers tend to stay within the nests where they care for the brood and 'milk' scale insects in or close to the nests.
Oecophylla weaver ants vary in color from reddish to yellowish brown dependent on the species. Oecophylla smaragdina found in Australia often have bright green gasters. These ants are highly territorial and workers aggressively defend their territories against intruders. Because of their aggressive behaviour, weaver ants are sometime used by indigenous farmers, particularly in southeast Asia, as natural biocontrol agents against agricultural pests. Although Oecophylla weaver ants lack a functional sting they can inflict painful bites and often spray formic acid directly at the bite wound resulting in intense discomfort.

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