ACROMYRMEX is a genus of
New World ants of the subfamily
* 1 Anatomy
* 2 Ecology
* 2.1 Reproduction * 2.2 Colony hierarchy * 2.3 Ant-fungus mutualism * 2.4 Waste management * 2.5 Foraging behaviour
* 3 Interactions with humans * 4 Species * 5 See also * 6 References * 7 External links
Profile view of an A. balzani worker
The antennae are the most important sense organs
Much of the inside of the
The heart is a long, tubular organ running the entire length of the
body, from the brain to the tip of the abdomen. It has valves within
it that prevent blood from flowing the wrong way. The fluids bathing
the internal organs is circulated by the heart; these fluids then
filter through the organs and tissues . The pharynx , which is part of
the gut , controlled by six muscles, pumps food into the oesophagus .
Debris in the food, such as soil, is filtered before it enters the
oesophagus and is collected in a tiny trap, the infrabuccal pocket.
When this pocket becomes full, the
Several glands in the head secrete various substances, such as those responsible for the digestion of food. Another gland within the head produces digestive and, in some species, alarm chemicals; these chemicals are used to alert nearby ants of impending danger, and any ant that detects this alarm will automatically go into "battle mode". If an ant is crushed, a huge blast of this chemical is released, causing the entire colony to go into "battle mode".
The thorax contains muscles to operate the legs and wings and the nerve cells to co-ordinate their movements; also contained in this part of the body is the heart and oesophagus.
The abdomen contains the stomachs , poison glands, ovaries in the
queen, and the Dufour\'s gland , among other things.
A. balzani worker carrying a leaf
Winged females and males leave their respective nests en masse and engage in a nuptial flight known as the revoada. Each female mates with multiple males to collect the 300 million sperm she needs to set up a colony .
Once on the ground, the female loses her wings and searches for a suitable underground lair in which to found her colony. The success rate of these young queens is very low and only 2.5% will go on to establish a long-lived colony. Before leaving their parent colonies, winged females take a small section of fungus into their infrabucchal pouches to 'seed' the fungus gardens of incipient colonies, cutting and collecting the first few sections of leaf themselves.
A mature leafcutter colony can contain more than 8 million ants (the
maximum size of the colony varies between species), mostly sterile
female workers. They are divided into castes , based mostly on size,
that perform different functions.
This mutualistic relationship is further augmented by another symbiotic partner, a bacterium that grows on the ants and secretes chemicals; essentially, the ants use portable antimicrobials . Leafcutter ants are sensitive enough to adapt to the fungus' reaction to different plant material, apparently detecting chemical signals from it. If a particular type of leaf is toxic to the fungus, the colony will no longer collect it. The only two other groups of insects that have evolved fungus-based agriculture are ambrosia beetles and termites . The fungus cultivated by the adults is used to feed the ant larvae and the adult ants feed on the leaf sap. The fungus needs the ants to stay alive, and the larvae need the fungus to stay alive.
In addition to feeding the fungal garden with foraged food, mainly consisting of leaves, it is protected from Escovopsis by the antibiotic secretions of Actinobacteria (genus Pseudonocardia ). This mutualistic microorganism lives in the metapleural glands of the ants. Actinobacteria are responsible for producing the majority of the world's antibiotics today.
Leafcutter ants have very specific roles for taking care of the fungal garden and dumping the refuse. Waste management is a key role for each colony's longevity. The necrotrophic parasite Escovopsis of the fungal cultivar threatens the ants' food source, and is a constant danger to the ants. The waste transporters and waste-heap workers are the older, more dispensable ants, ensuring the healthier and younger leafcutter ants can work on the fungal garden. Waste transporters take the waste, which consists of used substrate and discarded fungus, to the waste heap. Once dropped off at the refuse dump, heap workers organise the waste and constantly shuffle it around to aid decomposition.
INTERACTIONS WITH HUMANS
In some parts of their range,
In Central America, leafcutter ants are referred to as "wee wee" ants, though not based on their size. They are one of the largest ants in Central America.
Deterring the leafcutter ant Acromyrmex lobicornis from defoliating crops has been found to be simpler than first expected. Collecting the refuse from the nest and placing it over seedlings or around crops resulted in a deterrent effect over a period of 30 days.
* Acromyrmex ambiguus Emery , 1888 * Acromyrmex ameliae De Souza , Soares & Della Lucia , 2007 * Acromyrmex aspersus F. Smith , 1858 * Acromyrmex balzani Emery , 1890 * Acromyrmex biscutatus Fabricius , 1775 * Acromyrmex coronatus Fabricius , 1804 * Acromyrmex crassispinus Forel , 1909 * Acromyrmex diasi Gonçalves , 1983 * Acromyrmex disciger Mayr , 1887 * Acromyrmex echinatior Forel , 1899 * Acromyrmex evenkul Bolton , 1995 * Acromyrmex fracticornis Forel , 1909 * Acromyrmex heyeri Forel , 1899 * Acromyrmex hispidus Santschi , 1925 * Acromyrmex hystrix Latreille , 1802 * Acromyrmex insinuator Schultz , Bekkevold ">
* ^ A B Bolton, B. (2014). "Acromyrmex". AntCat. Retrieved 20 July
* ^ A B Piper, Ross (2007), Extraordinary Animals: An Encyclopedia
of Curious and Unusual Animals, Greenwood Press, p. 298, ISBN
* ^ "Archived copy". Archived from the original on 2012-02-02.
* ^ Zhang, M. M.; Poulsen, M. & Currie, C. R. (2007), "Symbiont
recognition of mutualistic bacteria by