On a single plot of rice paddy, at least six different types of\nspiders can be found living side by side, from wolf spiders and\nlong-jawed spiders to lynx spiders and tiny species numbering in the\ndozens per plot. They are not pests or a threat. They are all predators\nthat hunt planthoppers and other small insects that damage rice plants\ndaily. While many people shudder at the sight of spiders, farmers who\nunderstand the paddy ecosystem welcome their presence.<\/p>\n
It is important to note that spiders are not insects. Taxonomically,\nthey belong to the Arachnida class and have eight legs, unlike insects\nwhich have six. However, in terms of their benefit to farmers, spiders\nare on par with the best natural enemies from the insect world. Several\ntypes of spiders are commonly found in Indonesian rice paddies, each\nwith a different hunting strategy.<\/p>\n
The wolf spider (Lycosa pseudoannulata) is an active hunter that\ndirectly seeks and chases its prey. Its effectiveness depends on the\nsize and activity level of the target; it tends to be more effective at\ncatching less agile prey, such as green planthopper nymphs that cannot\nyet fly far. The lynx spider (Oxyopes javanus) has a distinctive\nappearance with hexagonal eyes and long, spiny legs, measuring about 7\nto 10 millimetres. It is highly productive, capable of preying on eight\nwhite-backed planthoppers a day. With a lifespan of around 150 days, a\nsingle female can produce up to 350 eggs in her lifetime, meaning the\npredator population can regenerate rapidly as long as its habitat is\nmaintained.<\/p>\n
Unlike the previous two types, the long-jawed spider (Tetragnatha\nspp.) employs a more passive hunting strategy. It tends to remain still\nduring the day, but at night it actively builds webs. Prey trapped in\nthe web is then captured and eaten. This type of spider has been\nrecorded preying on various planthoppers, including brown, green, and\nwhite-backed planthoppers. In several paddy field studies, Tetragnatha\nwas recorded as the most dominant spider species, especially in fields\nwith high brown planthopper populations, as these insects are a primary\nfood source.<\/p>\n
One of the most fundamental ecological principles is that predator\nabundance is directly proportional to prey abundance. The higher the\nplanthopper population in a field, the higher the spider population,\nbecause food is plentiful. This makes the presence of spiders an\nindicator that experienced farmers can read. A paddy field full of\nspiders is not a problematic field; on the contrary, it is a field where\nthe natural defence system is actively responding to the presence of\npests.<\/p>\n
Unfortunately, spiders are highly vulnerable to broad-spectrum\ninsecticides. Studies comparing fields using Integrated Pest Management\nwith those using conventional practices consistently find much lower\nspider populations in fields frequently sprayed with chemical\npesticides. When spiders are wiped out along with the target pests, the\npaddy\u2019s natural defence system collapses. Unlike natural enemies that\nneed to be specially cultivated in laboratories, spiders will come and\nbreed on their own as long as their habitat is not disturbed by\nunnecessary pesticides. Farmers do not need to do anything special to\nobtain the services of spiders; simply letting them live allows them to\nwork without being asked. The next time you see a spider web among the\nrice clumps, instead of feeling disgusted or disturbed, perhaps it is\ntime to see it for what it really is: a free safety net working to\nprotect the harvest.<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/why-farmers-actually-like-spiders-1782820421", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }