Saturday , May 15 2021

The study explains how two predators can benefit from cooperation



A study conducted by ecologists from the NUS Department of Biological Sciences showed that the crab spider Thomisus nepenthiphilus lives exclusively in the narrow Nepenthes gracilis plant and adds nutrients to its host. NUS PhD student Lam Weng Ngai is a key member of the research group. Credit: National University of Singapore

Two recent studies of ecologists from the National University of Singapore (NUS) have highlighted the relationship between the small pot plant and its "tenant", the crab spider Thomisus nepenthiphilus, which provides insights into the spider's little known feed management.


Thomisus nepenthiphilus is found only in the narrow Nepenthes gracilis pot plant, which is native to Singapore and can also be found in Indonesia, Borneo and Malaysia. Although the cactus plant is a carnivorous animal that fades and consumes insects to complement its nutritional needs, the crab spider Thomisus nepenthiphilus can utilize the coconut nectar of the cucumber to capture its byte while providing additional nutrients to its host.

"Our two studies provide important insight into the conditions that promote cooperation on parasitism, and the results are crucial for achieving a better understanding of these interactions," said researcher, Professor Hugh Tan, who is from the Department of Life Sciences at the NUS Faculty of Science.

The advantage of being "robbed"

In the first study, Assoc Prof Tan, together with Ph.D. student Lam Weng Ngai and former research student Miss Robyn, found that pots with no crab spider get more nutrients from each byte while they inhabited by tenants more byte but get less nutrients from each byte.

Their laboratory experiments found that crab spider bottoms fly that feed the potted plants and suck the body's body fluids. The crab spider then drops the buttocks, which still contain some nutrients, into the liquids in the jar to melt. As such, although the crab spider "steals" from the pot plant and gets the first flavor of the change, the net effect of this "break-in" can still benefit the potted plants as it gets the remaining nutrients from the exchange.

The results indicate that when there are scarce resources, this partnership between the crab spider and the pot plant is beneficial. But when the resources are plentiful, this partnership is not beneficial. The results of the study were published in the newspaper Oecologia August 14, 2018.

"A trend that has been observed in the recent mutualism research is that under more stressful conditions, the frequency and intensity of reciprocity between the different organisms increases. Our results support this observation. In other words, the aging adagen" a friend in need is a friend really "True not only to humans, but also to plants and animals," said Assoc Prof Tan.

Although the crab spider Thomisus nepenthiphilus "steals" the change from its host, the narrow potted plant Nepenthes Gracilis, a study by Ecologists from the National University of Singapore found that the net effect of this "burglary" could still benefit the pot plant as it gets the remaining nutrients from the switch thrown by the crab spider. Credit: Lam Weng Ngai, NUS Department of Life Sciences

Big change, big winnings

Assoc Prof Tan and Mr Lam also performed additional experiments in the plants' natural habitat. By field investigations, researchers identified predators that were found to be in larger numbers inhabited by spiders, and those who were not.

Laboratory experiments were performed to measure the nutritional content of these types of varieties to estimate how much nutrients could have if the perch had been caught and without the help of the crab spiders.

"Our results confirm the results of our previous study – T. nepenthiphilus crab spider really helps N. gracilis potted plants capture many different birds of prey. Even more important is the net contribution of T. nepenthiphilus to N. gracilis nutrition appears to be proportional to the size of the robe as T. nepenthiphilus prisoners, "explained Lam.

He drafted, "If the crab spider only catches small bites, such as mosquitoes or inkflies, the net benefit of the pot plant will be negative. It will be" stealing "nutrients from the pot plant. But when the crab spider catches big insects like cockroaches or big bugs, comes pot plant to benefit because the "service fee" paid to the crab spider becomes small compared to the total nutrients obtained through the interaction. Thus, the remaining nutrients that the potty grow from the carcasses thrown by the crab spider can be a good balance. "

The results of this study were published in Journal of Animal Ecology October 10, 2018.

Theoretical model to be built

Based on the insight from these two studies, the research group now builds a theoretical model on mutualisms that provides nutrients from one species to another. Such a model will allow researchers to investigate the factors that make mutualisms stable and monitor how changes in the environment, such as global warming or changing habitats, will change the ecological results.


Explore further:
Ants and carnivorous plants conspire for mutualistic feeding

More information:
Robyn Jing Ying Lim et al. Novell pitcher-spindle mutualism is dependent on the abundance of environmental resources, Oecologia (2018). DOI: 10,1007 / s00442-018-4246-8

Weng Ngai Lam et al. The crab spider-pot plant is a nutritious mutualism that depends on the byte resource quality, Journal of Animal Ecology (2018). DOI: 10.1111 / 1365-2656.12915


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