Thursday , March 4 2021

The study explains how two predators can benefit from collaboration.



Studies conducted by NUS biologists have shown that the crab spider Thomisus nepenthiphilus lives exclusively in the thinner pitcher Nepenthes gracilis and provides supplemental nutrients to its owners. NUS PhD student Mr Lam Weng Ngai is a key member of the research team. Credits: National University of Singapore

Two recent studies by an ecologist at the National University of Singapore (NUS) provide insights into the known small hunting behavior of spiders about the relationship between a slender pitcher plant and its spider spider Thomisus nepenthiphilus 'tenant' I will.


Thomisus nepenthiphilus is native to Singapore and is found only in Nepenthes gracilis, a slender pitching plant found in Indonesia, Borneo and Malaysia. The pitcher plant is an insect-eating predator to supplement nutrients, but the crab spider Thomisus nepenthiphilus uses honey to smell the sweet smell of the pitcher's plant, while at the same time providing nutrients to the owner.

"Our two studies provide an important insight into the situation in favor of co-operation with parasitics, and the results play a pivotal role in gaining a better understanding of these interactions." NUS's Associate Professor of Biological Sciences, (Hugh Tan) Faculty of Science.

Benefits of & # 39; snatching & # 39;

In the first study, Assoc Prof Tan, along with doctoral student Mr Lam Weng Ngai and former undergraduate Robyn Lim, found that turtleless pitchers received more nutrients from each food, People who eat more food, but eat less food from each food.

Their laboratory experiments found that crab spiders eat prey from pitcher plants and suck insect food fluids. Crab spiders consecutively digest the body of a food containing a small amount of nutrients into the body fluids of the pitcher. So the crab spider steals from the pitcher plant and gets the first taste of the feed, but the net effect of the 'burger' is still beneficial to pitcher plants as they gain residual nutrients from the feed can.

This study suggests that cooperation between crab spiders and pitcher plants is beneficial when resources are scarce. But when resources are abundant, this cooperation is not benevolent. The results were published in the journal. Oecologia August 14, 2018

"The trend observed in recent reciprocity studies is that the frequency and intensity of reciprocity between different organisms increases in stressful situations. Our findings support this observation, not for human beings A true friend for plants and animals, "Assoc Prof Tan said.

Though the crab spider Thomisus nepenthiphilus steals food from the host, Nepenthes gracilis, a slender pitcher plant, has shown a net effect of this 'burglar', according to a study by an ecologist at the National University of Singapore Has found that it can still help pitcher plants. Crab spiders get residual nutrients from the food they throw away. Credits: Lam Weng Ngai, NUS Department of Biology

Big prey, big profits

Assoc Prof Tan and Mr Lam also conducted additional experiments in the natural habitat of the plant. Field investigations have shown that more and more food has been found in pitchers with spiders and those without them.

Laboratory experiments were conducted to determine the nutrient content of this feed species to estimate the amount of nutrients the pitcher could obtain when the feed was caught in a trap without the aid of a crab spider.

T. nepenthiphilus Crab spiders have found that N. gracilis pitcher plants are really helpful in catching the food of many other species. More importantly, the net contribution of T. nepenthiphilus to nutrition of N. grapeis appears. It is proportional to the size of the food that T. nepenthiphilus catches, Lam explained.

"If the crab spider catches a small piece of food like mosquitoes or flies, the net profit of the pitcher's plant will be negative," he said, "and steals the nutrients from the pitcher's plant." But when a crab spider catches a giant insect such as a cockroach or a big bug, The feeding plant benefits because it reduces the amount of "pay" paid to the crab spider from the amount of total nutrients it has gained through the interaction. It is a good compromise. "

The results of this study Journal of Animal Ecology October 10, 2018

Theoretical model to be built

Based on the insights gained in these two studies, the team is developing a theoretical model of reciprocity that feeds nutrients from one species to another. Such a model will allow scientists to explore the factors that make relativity stable and monitor how environmental changes such as global warming and habitat alteration can change ecological consequences.


Additional information:
Ant and carnivorous plants eat reciprocal food.

Additional information:
Robyn Jing Ying Lim et al. The novel pitcher plant – spider mutualism depends on abundant environmental resources, Oecologia (2018). DOI: 10.1007 / s00442-018-4246-8

Weng Ngai Lam et al. Crab-pitcher plant relationships are nutritional mutualism, which is dependent on the quality of food resources, Journal of Animal Ecology (2018). DOI: 10.1111 / 1365-2656.12915


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