BABY GOT BACK!

Introduction

Does biome affect liquid foraging rates of Crazy Ants {Paratrechina longicornis}?

• Does biome affect the number of engorged vs. the number un-engorged ants entering biosphere 2?

• Does biome affect the percent engorged vs. percent un-engorged entering biosphere 2?

• Are there different rates of engorgement among colonies?

• Are there different rates of engorgement among different colonies within a biome?

• Does biome affect the total number of crazy ants entering the biosphere 2?

Introduction

Methods

• Identified two points of entry for both desert and rainforest biome.

• Counted total number of crazy ants entering biosphere

• Counted number of crazy ants engorged

• Counting occurred inn a set period of two minutes

• Ten replicates for each point of Entry

• Non-parametric Tests (Mann-Whitney Test, Kruskal-Wallis Test)

Results

Eli’s nap time

There is significant difference between the number of engorged individuals entering the rainforest and desert biomes. There is also significant difference between the number of unengorged individuals entering the rainforest and desert biomes. (Engorged, Mann-Whitney U Test, Z1,38 = -2.677, p = .007; unengorged, MWU, Z1,38 = -4.117, p = .000)

There is significant difference between the percentage of engorged individuals entering the rainforest and desert biomes. There is significant difference between the percentage of unengorged individuals entering the rainforest and desert biomes. (Percent engorged, MWU, Z1,38 = -2.448, p = .014; percent unengorged, MWU, Z1,38 = -2.448, p = .014)

There is significant difference among colonies in the number of engorged and unengorged individuals entering the biosphere. (Engorged, Kruskal-Walis Test, 3,36 = 16.735, p = .001; unengorged, KWT, 1,36 = -18.618, p = .000)

Within the desert biome, there is significant difference among colonies in rates of entry between of engorged individuals. Within the rainforest biome, there is significant difference among colonies in rates of entry between the engorged individuals. In both biomes there was no significant difference among colonies in the number of unengorged ants entering biosphere2. (Desert engorged, MWU, Z1,18 = -2.480, p = .013; unengorged, MWU, Z1,18 = -0.379, NS); (Rainforest engorged, MWU, Z1,18 = -2.432, p = .015; unengorged, MWU, Z1,18 = -1.476, NS)

There is significant difference between biomes in the number of total ants entering the biosphere. (Total, MWU, Z1,38 = -3.994, p = .000)

Figure 1Average Total Ant Flow Across Biomes

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Figure 2

Average Percent Engorged

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30.27%

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DiscussionThere was a greater percentage of

engorged ants entering the rainforest biome than the desert biome and there were fewer total ants entering the rainforest, possibly because fewer ants had to carry more liquid back. However, we did not measure the size of the colonies so it could be that the percentage of the ants going out is the same for both biomes. Also, there could possibly be more resources outside the rainforest biome than the desert biome so the rainforest ants would have more success in finding liquids.

The reason that there was more ant flow into the desert biome could be that there are less resources in the desert biome than in the rainforest biome so there is a greater need to forage outside of the biosphere.

We analyzed the data as if the two holes were separate replicates. However, the holes were within the same biosphere and not from separate locations.

It is difficult to generalize either biome because of the statistically significant variation among the colonies within the respective biomes. Possible sources of error included misidentification of engorged ants and duplication of counting.

Conclusion

Based upon our results:

• There was a significantly higher percentage of engorged ants entering the rainforest biome.

• There was greater total ant flow in the desert biome.

References

ReferencesDanoff-Burg, James. 2000. Module 14: Ecological Impacts of a Single Introduced Ant Species.