best Leaf Cutter Ants images on Pinterest | Ants, Ant and Leaves
A compilation of leaf-cutter phorid species with their known and/or potential host . Apocephalus flies attack both ant genera with 8 recorded species .. ant activity/trial, and number of trails, then a positive relationship could. Atta cephalotes L., the predominant leaf-cutting ant species found in coffee farms in .. Relationship between total colony density and percentage of shade in for their advice in statistical analyses; and José González for providing taxonomic to food sources and the decrease in natural enemies, especially phorid flies, . Leaf-cutter Ant Carrying Leaf Piece On Tree Log Tree Logs, Career Advice, Note the small ants riding atop the leaves- these stand guard against parasitic Phorid flies . These ants have a symbiotic relationship with organisms that create.
For comparison, we determined the number of foragers for three nests nests 1, 5, and 6. We also measured the total length of foraging trails. The number of foragers present both laden and unladen was counted three times in three cm sections along each trail during a foraging activity peak. We determined the mean number of foragers per cm section per trail and multiplied this number by the total trail length to estimate the total number of foragers.
This is likely to be an underestimate of total forager number, as it only counts foragers on main trails. The number of laden foragers entering the nest was counted for 3 min hourly for 5 h during a foraging-activity peak. Division of labor Nest 5 was selected to test the hypothesis that waste management is an alternative endpoint to foraging for workers outside the nest and that waste workers do not become foragers or vice versa.
Such a division of labor would prevent waste workers from contaminating leaf fragments entering the nest, which would occur if they became foragers. The methods used also allowed us to investigate the division of labor between waste transporters and heap workers. In particular, we tested whether waste transporters become heap workers and vice versa. Do foragers ever become transporters or heap workers?
Two groups of and foragers were paint-marked over a 3-day period on the pronotal spines of the thorax using carbody paint applied with a seeker. Group 2 workers were marked 6 weeks after group 1 and were also used in the recruitment experiment see below. The heap was observed for two min periods each morning and evening for a total of 20 days between 15 March and 3 April giving 40 observation periods.
Marked ants working as either transporters or heap workers were noted. Marked heap workers were removed. We also observed foraging trails to ensure that marked foragers were still alive. Do transporters become heap workers? Two groups of and transporters were marked as above but with a second color. The heap was observed for two min periods each morning and evening for the following 20 days giving 40 observation periods. Any marked heap workers were removed.
As above, we also observed the transporters to ensure that marked individuals were still alive.
Do heap workers become transporters? Seventy-six heap workers were marked over 4 days with a third color, and their presence or absence on the heap or transporting trails was observed daily for two min periods. Weights of workers To determine whether there was a size-based division of labor among foragers, waste transporters, and waste heap workers, we took 50 foragers, 50 transporters, and as many heap workers as could be collected from each of 13 nests and weighed them.
Transporter recruitment The group of marked foragers was also used to investigate whether foragers are recruited to waste management if the number of waste transporters is drastically reduced. We counted the number of waste transporters per minute for 3 min every 30 min for 60 min as they emerged from the waste exit.
Then approximately transporters were removed over 60 min. We recorded the waste output rate and the presence of marked foragers among transporters over the next 3. The number of heap workers was also recorded. Waste-directed aggression Hart and Ratnieks showed that in laboratory colonies of Atta cephalotes, both foragers artificially contaminated with waste and waste heap workers were subject to heightened aggression from nest mates.
Psyche: A Journal of Entomology
They proposed that this aggressive response to waste-contaminated ants helps prevent waste workers from leaving the heap and thereby contaminating the fungus gardens Hart and Ratnieks, We investigated whether similar aggression occurred in A. First, we determined whether ants working with waste transporters and heap workers were subject to heightened aggression from nest mates.
Taking the three forager groups, 25 foragers from the remaining forager stock were individually introduced to forager group 1. Twenty-five workers from the transporter stock were similarly introduced to forager group 2.
Finally, 25 workers from the heap worker stock were introduced to forager group 3. We performed similar introductions for the three transporter and three heap worker groups, giving all possible combinations of resident worker group and introduced workers. For each introduction, any aggression, defined as resident ants biting the focal ant, was noted, and the focal ant was removed before the next introduction.
This was repeated for five colonies. Second, to investigate the effect of waste contamination, a separate group of 25 foragers was housed for 3 h in a petri dish half-filled with waste and introduced, following the same procedure as above, to a group of 25 foragers.
Waste heap location We tested two hypotheses concerning how the juxtaposition of the waste heap and foraging trails can be adaptive in terms of colony hygiene. First, we hypothesized that heaps would be located downhill from forage entrances to prevent rain from washing waste back into the nest and that heaps could be closer to forage entrances when the colony was situated on a steep slope.
Second, we hypothesized that foraging trails do not pass close to heaps, to prevent foragers from becoming contaminated with waste. For colonies with a single forage entrance, we measured the shortest distance along the ground between the hole and the heap.
The slope of the ground to the heap was measured using a clinometer. The orientation of foraging trails as they left the foraging entrances was measured with a compass relative to the heap-entrance line. Any unusual additional features of waste heap location were also documented. Heaps were up to Three colonies were depositing waste into ponds. Twenty-two colonies had waste heaps around the bases of trees, and two colonies were depositing waste along the length of a fallen tree trunk, forming linear heaps, both approximately 5 m long.
The remaining 23 colonies were depositing waste onto heaps on areas of the forest floor with no obvious features. General features of waste disposal Typically, ants carried waste from an exit hole located between the foraging entrances and the heap on a well-maintained trail. The loads were either placed directly onto the heap or dropped onto the heap from an elevated position, such as a tree branch or trunk if the heap was around a tree base observed in all 22 tree-base heaps and 4 forest floor heaps near overhanging rocks.
Workers were continuously present on the heaps of all but seven of the smallest nests. These workers moved waste around the heap. Tunnels were sometimes present within the heap observed in 8 of 50 colonies. In addition, heap workers carried dead ants to the heap margins observed in 12 of 50 colonies. Heap workload Waste disposal was constant throughout the day and night, both with respect to number of loads and weight per hour. In contrast, foraging showed a strong increase in both numbers of foragers and weight of forage between h and h Figure 1.
Waste removal occurred at all observation times for the 11 other study nests. The total estimated number of waste loads exiting the nest in 24 h wascompared toforage items entering. However, although waste loads had a mean fresh mass of 2.
Therefore, the total mass of forage brought in was g, compared to g of waste removed. This nest had waste workers see belowso each waste worker made, on average, 33 trips in 24 h. Figure 1 Daily tempo of foraging and waste removal activity in nest 5. The weight of waste removed per hour remains constant throughout the day.
Foraging activity peaks between h and h. Number of workers involved in waste disposal The six focal nests had transporters andforagers Figure 2. Pooling results across all colonies, This latter group of phorids are extremely valuable to forensic entomologists.
Waste management in the leaf-cutting ant Atta colombica | Behavioral Ecology | Oxford Academic
But as fascinating as these life styles are, it is those that consume ants heads from the inside that naturally I was most interested in. The brain-eaters Parasitoid phorid flies are the scourge of many ant species. As the ants forage outside their nests, phorids stalk their hosts, hovering above them menacingly.
The march is halted as the ants head falls off, decapitated by the secretion of neck-membrane dissolving enzymes produced by the developing fly. A grizzly but amazing lifecycle. Pseudacteon curvatus ovipositor used for injecting an egg into its ant hosts. Photo credit Sandford Porter, hosted wikicommons.
Leaf-cutter ant video - Atta cephalotes - 03 | Arkive
Their ant hosts even include the charismatic leaf-cutter ants, who have evolved their own intriguing defence behaviours. Within the leaf-cutter genus Atta, the largest workers sever leaf sections to transport back to the nest on which they cultivate a fungus that is their true food source.
Whilst carrying their burdens, however, their mandibles are out of action to defend themselves from shadowing flies.
See caption for information. A hope for controlling alien invaders? But although superficially gruesome, these flies could be our saviours in an important issue.