The Yellow
CRAZY
The Yellow Crazy Ant (Anoplolepis
gracilipes) shown in Picture 1, "was accidentally introduced to Christmas Island between 1915 and
1934, and became widespread throughout the island" (Australian Department of the
Environment and Water Resources, 2007). "It has been
introduced into parts of Africa (including South Africa), Asia (including India,
Myanmar, Malaysia, Indonesia, New Guinea and Sri Lanka), South America
(including Brazil) and Australia. It has been introduced onto some Caribbean
islands, some Indian Ocean islands (including the Seychelles, Madagascar,
Mauritius, Reunion, the Cocos Islands and the Christmas Islands) and some
Pacific islands (including New Caledonia, Hawaii, French Polynesia, Okinawa,
Vanuatu, Micronesia and the Galapagos archipelago) (McGlynn 1999; Holway et
al. 2002; Lewis et al. 1976, Haines and Haines 1978a, Veeresh and
Gubbaiah 1984, in ODowd et al. 1999)" (Dr. Dennis O'Dowd, 2007).
The native region is not known at this time although some sources say it
originated maybe from Africa or Asia. This pest species was first spread
unintentionally by people, but can be dispersed agriculturally, by boat and
other means of transportation, and natural dispersion. "The Name "crazy ant" was derived
from their frantic movements and frequent changes in direction, especially when
disturbed" (Australian Department of Environment and Water Resources, 2007).
Picture1
Characteristics: long legs and antennae, yellowish-brown and sometimes pale yellow color body, largest invasive ant species, kills prey with formic acid, body size can range from 1-2mm to 5mm long, form super colonies
Kingdom: Animalia Phylum: Arthropoda Class: Insecta
Order: Hymenoptera Family: Formicidae Genus: Anoplolepis
Species: A. gracilipes
The yellow crazy ant can be found in a many number of places such as "agricultural areas, coastland, natural forests, planted forests, range/grasslands, riparian zones, ruderal/disturbed, scrub/shrublands, urban areas, water courses" (Dr. Dennis O'Dowd, 2007). The yellow crazy ant can inhabit both disturbed and undisturbed areas as well.
Defense Mechanism to its Potential Prey and Predators:
It will spray formic acid and then eat the prey/predator.
Picture
2 shows a crab that has been killed by yellow crazy ants.
Significance of Their Body: The yellow crazy ant has a relatively long body especially the workers in the super colonies. The large body can be used as an advantage in efficient working among the super colonies in transporting food. Although the ant is small, the A. gracilipes is the largest of the invasive ant species. It is able to kill its larger prey that ranges from invertebrates up to small mammals, by spraying formic acid. Dr. Dennis O'Dowd has described the workers as having "yellow-brownish body colour, and is weakly sclerotized" and "a long slender gracile body, with the gaster is usually darker than the head and thorax" (2007). In some instances the body is able to act as a camouflage from other predators. Picture 3 below shows how easily the yellow crazy ant can use its body to blend in with its environment.
Lifecycle and Reproduction: About 76-84 days is basically the life cycle of the yellow crazy ant (Dr. Dennis O'Dowd, 2007). "Eggs hatch in 18-20 days, and worker larvae develop in 16-20 days. Pupae of workers require around 20 days to develop while those of queens develop in 30-34 days" (Dr. Dennis O'Dowd, 2007). The A. gracilipes species is able to reproduce year-round and typically reproduce before a rainy season (Dr. Dennis O'Dowd, 2007). Dr. Dennis O'Dowd also adds that since the colonies are polygynous, "colony budding is an important form of dispersal for the ant" (2007).
Food: The yellow crazy ant feeds on a large number of prey ranging in size. They can eat fauna ranging from small isopods up to large number of mammals. The yellow crazy ant can also feed on litter and other canopy fauna. O'Dowd adds that "in addition to protein-rich foods A. gracilipes may rely heavily on carbohydrate-rich nutrient sources such as plant nectar or honeydew-producing scale insects (especially insects in the Homoptera genus)" (2007). The yellow crazy ant will compete with other ant species for food which in return will help keep the invasive ant species low. The yellow crazy ant diet will also differ based on where the species is located; they can only feed on what is available to them. As mentioned before, the yellow crazy ant will spray formic acid in order to subdue their prey or predators in order to obtain its food. Most ants in general need to have carbohydrates and proteins in their food for survival needs.
Super colonies: The A. gracilipes species is known greatly by
its ability to form super colonies. A super colony is a huge colony of
these yellow crazy ants that does more harm than good. These super
colonies infest the land and prevent the native species from growing back and
disrupt a lot of ecological processes. The super colonies will stretch
over many acres of land and consist of many queen ants. These multiple
queens to super colonies is what sets this ant species apart from other ant
species which only have one queen to a nest. One super colony can have
over thousands of yellow crazy ants. Most of these super colonies infest
Australia and there are many concerns about the spread of these super colonies.
The boundaries of these super colonies can have a huge impact on densities of
the yellow crazy ant (Abbott, 2006). For more on Abbott's super colony
experiment refer to reference 4. As super colonies
continue to grow and expand, more native species will die and the yellow crazy
ants will take over the environment and pose more threats.
Picture 4
shows a small portion of a super colony feeding on a red land crab.
Positive and Negative Effects of Yellow Crazy Ants on Systems: Nominated in the top 100 of the World's Worst Invasive Species List, the yellow crazy ant has a lot of negative effects and just a few positive effects. This negative effect is due to the numerous super colonies. The super colonies of ants are contagious as they spread throughout its surrounding regions killing native species in their path. For instance, the yellow crazy ant will kill red land crabs which provide more proteins and nutrients to the ant species. As these yellow crazy ants infest over 25% of Christmas Island, they have "displaced an estimated 15-20 million crabs" (Australian Department of Environment and Water Resources, 2007). Consequently, as the crabs die, the small scale insects increase in numbers which creates a cascade of events such as forest trees die, light enters the canopy, and finally weed invasion (Australian Department of Environment and Water Resources, 2007). The only positive effect of the yellow crazy ant invasion is the increase in small scale insect activity, and even then it produces a long term negative effect. The yellow crazy ant has the ability to invade and spread through agricultural systems which leads to crop death and eventually economic lost in the farming industry. Since the yellow crazy ants can be transported to other areas by means of boats, cars, etc, the natural hosts such as timber and soil could be disrupted causing more economic lost. These yellow crazy ants are more of a pest when they invade the cracks and crevices in homes. As mentioned before, the yellow crazy ant feeds on almost anything so as it kills its prey, the number of a particular prey species will be reduced which can eventually lead to extinction of that species. As the yellow crazy ant species continues to invade new territory, another economic system will be disrupted. This economic lost will be in the tourism industry. People travel the world looking at certain exotic and native species to a certain area, if the species is wiped out by the yellow crazy ant, then tourism of that area will decrease and the economy will decline. All in all, the yellow crazy ant will invade anything in its path and then kill and eat it, causing more damage than one could imagine.
Picture 5 below shows a forest section on Christmas Island before the invasion of the yellow crazy ant.
Picture 6 below shows a forest section on Christmas Island after the invasion of the yellow crazy ant.
Controlling the Issue: There have been several means of control of the yellow crazy ant. The basic methods of control are poison baiting, education, and of course research (Australian Department of Environment and Water Resources, 2007). Most forms of control must meet certain criteria such as is it harmful to other animals? humans? and water? As long as these criteria are met, then the method of control is approved and used. Fipronil is a type of bait discoverd by Bayer Crop Science and Animal Control Technologies that is found in a fish protein base and is very effective in fighting against the yellow crazy ant species (Australian Department of Environment and Water Resources, 2007). The costs of maintaining control of the yellow crazy ant have been enormous. "The Australian Government has spent more than $2.5 million on controlling crazy ants over the past 7 years, $700,000 of which has been funded under the Natural Heritage Trust" (Australian Department of Environment and Water Resources, 2007). Other baiting material will include chemicals that act as a stomach toxin. These toxins include "hydramethylnon (Maxforce, Amdro), sulfuramid, and sodium tetraborate decahydrate (Borax)" (Dr. Dennis O'Dowd, 2007). These toxins should be designed to fit the natural environment of the yellow crazy ant. All aspects such as location, size, behavior, and foraging habits should be noted when distributing these baits. As for the education and research methods, there have been several printouts about the issue distributed to numerous people, and several research groups have been formed to provide more information on the yellow crazy ant and its imposing problems. Because of the rapid dispersal of the yellow crazy ant, there should be some immediate attention to this issue and more methods of control should be on the top priority list.
Picture 7 shows an example of a baiting technique used.
General Information About Ants: Ants are considered to be the most abundant pest problem in households today. "The most commonly encountered pest ants are pharaoh, ghost, carpenter, native fire, imported fire, crazy, thief, acrobat, and big-headed ants" (Koehler et al., 2007). Ants can come in all sorts of colors such as red, black, tan, purple, green, blue, and brown. Ants can infest food and structures around the home, and even build those ever abundant mounds found throughout the yard. Some ants can even be harmful such as the red fire ant which has been known to be harmful to humans after they bite. Generally ants have two parts, the abdomen and thorax, and bent antennae and six legs. Some ants even have wings while others do not. Ants are very organized and have a particular way of doing tasks. Ants live in enormous groups working together to make their colony successful and that is why ants are very sociable and usually have one queen to each colony. Although some species of ants will have more than one queen to each colony or super colony. The queens are usually the reproducers of the group while males usually die after the mating season. The workers are females that cannot reproduce. "The function of the worker is to construct, repair, and defend the nest; and feed the immature and adult ants of the colony, including the queen" (Koehler et al., 2007). The queens act as the mother and leader of the colony. New colonies can be formed by budding and during mating season of the winged reproducers (Koehler et al., 2007). As the female and male winged reproducers land in new territory, the young are produced. The continual reproduction of young ants will make the colony larger. Ants have a few stages during their lifecycle which include the egg, larva, pupae, and adult stages. The eggs of course will hatch into larvae, then the larvae will form pupae, and pupae into adults. The usual lifecycle timeline includes "six weeks to 2 months are required for development from egg to adult in some species" (Koehler et al., 2007). Budding will occur when a queen and some of her workers will travel to new territory to establish a new colony, for example "pharaoh ants, some kinds of fire ants, ghost ants, and Argentine ants spread colonies by budding" (Koehler et al., 2007). The ants usually burrow underneath the ground forming tunnels and then have rather huge mounds on top of the soil. The ants will flourish in warm climates and will not live in cold climates. Ants can maintain a diversity of food groups, but sometimes appetite is species dependent. Such species dependent on specific foods are fire ants which "feed on honeydew, sugars, proteins, oils, seeds, plants and insects", pharaoh ants which "feed on sugars, proteins, oils and insects", crazy ants which "like sugars, protein, and insects"; and carpenter ants which "prefer sugars and insects" (Koehler et al., 2007). Ants also rely heavily on water, carbohydrates, and proteins in their diet. Each species of ants will have their own way of defending themselves such as the yellow crazy ant spraying formic acid, and the red fire ant biting its prey. While some ants can be harmful others can be helpful and actually have some benefits. Some ants will eat unwanted plants, their tunnels allow air to enter the soil, spread seeds, and decompose materials (Bubblegum Productions, 1998). Below are a few examples of ant species.
Picture 8 shows a crazy ant Picture 9 shows a Florida carpenter ant
Picture 10 shows a ghost ant Picture 11 shows an imported fire ant
References:
1. Australian Department of Environment and Water Resources. Christmas Island National Park. Yellow Crazy Ant. 2007. http://www.environment.gov.au/parks/christmas/fauna/crazy.html (Pictures 1, 2, 5, 6, and 7 are also found from this website)
2. O'Dowd, D. Dr. Anoplolepis gracilipes. 2007. http://www.invasivespecies.net/database/species/ecology.asp?si=110&fr=1&sts=sss
3. Picture 3 is courtesy of Google Images. http://images.google.com/images?sourceid=navclient&ie=UTF-8&rls=GGLG,GGLG:2005-41,GGLG:en&q=the+yellow+crazy+ant&um=1&sa=N&tab=wi
4. Abbott, K. L. Spatial Dynamics of Super Colonies of the Invasive Yellow Crazy Ant , Anoplolepis gracilipes, on Christmas Island, Indian Ocean. Diversity and Distributions. 2006. 12:101-110.
5. Picture 4 is courtesy of P. Lester. The Pacific Ant Prevention Programme. 2006. http://images.google.com/imgres?imgurl=http://www.issg.org/cii/PII/img/PAPP/Crab%2520and%2520Anoplolepis.jpg&imgrefurl=http://www.issg.org/cii/PII/PAPP.htm&h=327&w=371&sz=62&hl=en&start=8&um=1&tbnid=3eeChy7jTUY9xM:&tbnh=108&tbnw=122&prev=/images%3Fq%3Dthe%2Byellow%2Bcrazy%2Bant%26ndsp%3D18%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DGGLG,GGLG:2005-41,GGLG:en%26sa%3DN
6. Koehler, P. G., Pereira, R. M., Oi, F. M. Institute of Food and Agricultural Sciences, University of Florida, Gainesville. Ants. 2007. http://edis.ifas.ufl.edu/IG080
7. Bubblegum Productions. Ants. 1998. http://www.bubblegum-productions.com/anthony/ants.htm
8. Pictures 8, 9, 10, & 11 are courtesy of James Castner, Institute of Food and Agricultural Sciences, University of Florida. 2007. http://edis.ifas.ufl.edu/IG080.