Natural History Of A Sit And Wait Dipteran Predator That Uses Extrafloral Nectar As Prey Attractant

The original article with the above title has all the components of a scientific paper. I think the title adequately described everything about the content of the paper. The abstract was well described because it briefly stated the main objectives of the research, methodologies used, and the results obtained. Their main objectives were to describe the oviposition of the fruit fly adult, Rhinoleucophenga myrmecophaga, larval of the fruit fly and their interaction with their prey. They wanted to provide evidences that the fruit fly larvae use ants as prey and use extrafloral nectar produced by the plant Qualea grandiflora to attract their prey. The article contains the strategies and behavior of the ants and the dipteran larva predator.

They were able to observe the oviposition by the R. myrmecophaga, their eggs are laid near the EFNs, and after three days they hatch into larvae and move to the EFNs where their shelters are built. Many sit and wait predators are often exposed to danger of being attacked by a predator, but for the case of R. myrmecophaga, there is reduced risk as the shelter they make from nectar and other materials serve not only as a trap for preys but also serve as a strategy to protect themselves from natural enemies and other abiotic factors. They also found out that different ant species under the subfamilies Formicinae, Myrmicinae and Pseudomyrmecinae visited the plants at different time of the day. About 94% of the insects visiting the shelters constructed by the larvae were ants and the rest are in the order Diptera, Coleoptera, and family Vespidae. They conducted stable isotope analysis (δ15N and δ15C) for the predators, Qualea leaves, ants and the non-lepidopteran herbivores to determine the trophic level, δ15N values for predators especially R. myrmecophaga had significant differences compared to the rest of the samples while δ15C values were similar for both R. myrmecophaga and ant samples analyzed. This shows that the R. myrmecophaga has the highest trophic values compared to other samples analyzed, especially in comparison to the ants. Similar nitrogen ratio seen in R. myrmecophaga was also seen in the lepidopteran larvae that feed on the leaves of Q. grandiflora. The chemical analysis of the EFN of Q. grandiflora with the help of the hand refractometer shows that it had about 87% sugar content and results also show that the EFN and the droplets released by the R. myrmecophaga show similar pattern of molecular mass which means that the EFNs are used to attract and trap their prey before feeding on them.

They did a good job by doing all the studies they did to know if the fly larvae truly use the EFNs of the Q. grandiflora to attract and trap prey (ant) that it eventually uses as food. However, what I would change is the title and the fact that even without the dipteran predator, the EFNs of the Q. grandiflora are always there and have always been used by the ants as a food source so I would not say it is a prey attractant, I would say or think that the R. myrmecophaga uses it for its own benefit since they construct their shelter right at the EFNs. Also, no application of this research was further explained, for example the potential impact of the presence of the R. myrmecophaga on these mutualistic ants and other herbivores that may be visiting the Q. grandiflora plants.

In the future, ants might evolve ways to defend themselves in order not to be trapped down at the shelter of the fly larva, or they might avoid visiting the EFNs of the Q. grandiflora plant. If the latter is done, the protection the ant gives to the plants will be reduced and the ants might not be able to use the EFN as food source and they might look for other options as a food source. It will also be nice to conduct research to know if the presence of the R. myrmecophaga has some negative effects on the Qualea plants since there is ant-plant mutualism between the ants and Qualea plants. The question to be answered is if the present or absent of ants decrease or increase herbivory and herbivore abundance on Q. grandiflora plants and the EFNs. More observations should also be done to see if there are other sit and wait predator like that of the fruit fly larvae to be more informed by these kinds of strategies that may be used by insects to attract, trap and use other insects as prey even when they are not serving a mutual function with the plant or other hosts that may be involved. Another interesting thing to do is a chemical analysis of what their shelter is composed of in order to know what is involved during the process of shelter building.