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Leaf-cutting Ants
Dátum pridania: 30.11.2002 Oznámkuj: 12345
Autor referátu: neuvedeny
 
Jazyk: Angličtina Počet slov: 3 882
Referát vhodný pre: Stredná odborná škola Počet A4: 11.9
Priemerná známka: 2.98 Rýchle čítanie: 19m 50s
Pomalé čítanie: 29m 45s
 

Day by day she grows thinner while caught in a race between starvation and creation of enough ants that can sustain her life. With the queen’s resources rapidly running down she must create a perfectly balanced work force on her first try. In the first crop of adult workers, there are no soldiers or larger-sized workers. Only the smallest foragers and still smaller workers who raise the fungi are present When the workers emerge they immediately begin to feed on the fungus and then dig their way up to the surface and bring leaves to sustain the fungus garden. The queen now turns into an egg laying machine. All she does is eat and produce eggs while the colony does the rest of the work. As the colony grows and prospers and size range of workers expands to include larger and larger forms. When the colony reaches about 100,000 members, the first full-sized soldiers are present. The colony’s beginning is slow but during the 2nd and 3rd years its growth is accelerated. When the colony begins to produce winged males it is a sign that the queen is old and soon the colony dies (Holldobler & Wilson, 1994).

When the queen first starts to lay eggs, Holldobler & Wilson (1994) found that the heads of the ants produced were in the range of 0.8 to 1.6 millimeters (heads of ants are proportional to body length, the larger the head, the longer the body). If the heads are greater than 1.6 millimeters, the queen will have lost too much energy in producing them and she will die along with the colony. If the heads are less than 0.8 millimeters, the ant is useless because it is too small to carry leaves and too small to care for the fungus garden(s). Now you must be asking yourself, how does the queen know what distribution of offspring to produce first? Holldobler & Wilson (1994) found that it is the size of the colony, not its age that determines that caste distribution. Example, if you took a large colony of leaf-cutting ants and killed all of the ants except 10,000. The queen would not produce huge soldier ants but would concentrate on producing small and medium sized ants until the colony reached a certain size. In essence, by killing the ants you made the colony young in its size and caste configuration (my example). Another reason for the unique distribution of the roles and sizes of ants is related to physics and chemistry. In each role of each size of ant, Holldobler & Wilson (1994) found that when they measured carbon dioxide given off, that the ants minimized the amount of carbon dioxide given off.
 
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