Baiting for insects
Many insects, such as ants, nitidulid beetles, dung beetles, carrion beetles, bark beetles, moths, and others are attracted to various baits. Baits can be used be applied to the ground, on trees, ropes, or elsewhere, and insects can be collected directly from them. Alternatively, certain types of traps can be baited with specific baits and the insects collected from the trap container. Several different types of bait we use in the MEM are give below.
General baits for Ants. I have used several different baits to collect some ant species. including cookies (Keebler Sandies Pecan Shortbread®), tunafish (StarKist® chunk light in water), hotdogs (Bar S®, chicken, beef, & pork), Spam® and peanut butter (various brands). The Keebler sandies are especially effective at luring major workers of Pheidole spp. out of their nests in the ground. In addition, it can be plastered to the bark of trees quite easily. I have collected many species of ants at this bait and I highly recommend it, although I cannot take credit for initially using it for bait. It was suggested to me by Mark Deyrup, an eminent ant taxonomist at Archbold Biological Station in Florida. Tuna is also a good bait for ants and I have placed a small amount in vials, then simple placed the open vials on the ground until ants found them. After a reasonable amount of time (30 minutes to an hour, for example), the vials can be capped and picked up. Like tuna, hotdogs are attractive to some ant species, however, the specimens collected tend to get oily from the hotdogs. Peanut butter is an excellent bait for some arboreal species of ants and it can be slathered on trees and checked periodically for ants. I have heard (from the world renowned Gary Umphrey at the University of Guelph, Canada) that some Aphaenogaster species love cheddar cheese. Undoubtedly, there are as many baits as there are items in grocery stores, so use your imagination.
Brown sugar yeast bait. One of the easiest ways to collect many species of nitidulid beetles (also called sap or picnic beetles) is by putting out some type of bait, especially something sweet and rotting. A common method we use is putting a mixture of water, brown sugar, and yeast (mixed in a ratio of 2 cups of water, 1 cup of brown sugar, and 1 packet of Brewers yeast) in either a mason jar at the base of a tree or in some type of container which is hung from a tree limb. The trap should be checked after two or three days and new bait added. Insects can be collected by dumping the trap contents into a kitchen strainer, then pouring the insects into a jar of alcohol (70% ethanol). If the mix was placed in a mason jar, the lid can be placed on it in the field and it can carried back to the lab (or wherever you would like to carry it) where it can be rinsed with alcohol later. As an alternative to this method, we sometimes put the mixture in a pitfall cup in the ground to make the bait more accessable to a greater variety of insects, especially those that may be flightless or less apt to readily fly. Many insects other than sap beetles are collected in these bait traps including ants (especially carpenter ants), moths, flies, flower feeding scarab beetles, staphylinids, etc. This is not a good way to collect the moths, however, because they will not be in good shape. Another good way to collect sap beetles (and some scarabs, etc.) is by putting out cantaloupe or other melon rinds, or various types of rotting fruit in a bucket. Check the bucket daily and see what you get.
Carrion/dung Bait. There are many species of insects that specialize in feeding on carrion or dung. Carrion feeders include such things as carrion beetles (Silphidae), small carrion beetles (Leptodiridae), some nitidulid beetles, some staphylinid beetles, and many others. Many insects also find dung to their liking, with some of the scarab beetles among the most infamous. An easy way to sample either carrion or dung feeders is to hang a small mesh bag (or open carton, or something similar) from the cover of a pitfall trap with the bait inside of it. Insects attracted to the bait will fall into the pitfall trap. For carrion bait, we have had success with raw chicken, and for dung traps, any variety of dung will work, such as deer, pig, etc. Some dung feeders are apparently quite finicky about the type of dung they prefer, so you may get different things by using different kinds.
Turpentine. Some wood boring beetles and other insects are attracted to turpentine. We sometimes combine a Lindgren funnel trap with turpentine to attract beetles, especially some bark beetles. The turpentine is poured into a small jar with a lid having a cotton or other type of wick running through it to the turpentine. The jar is then placed inside one of the funnels on the trap.
Beer/Molasses Bait. A mixture of beer and molasses of equal parts can be prepared and simply placed in a bucket and hung from a tree limb. This sort of bait is good for attracting various beetles, especially some cerambycid beetles (longhorn beetles). Insects fly to the bait and land in it. They have to be strained out with some type of strainer; a small kitchen strainer works fine. Insects collected by this method need to be rinsed with alcohol before being prepared. There are differences in opinion on what brand of beer is best for attracting insects. Some insist upon only using the best dark beer. However, I just can't bring myself to put good dark beer in a bait for bugs, so we have used cheap canned beer with some effectiveness. There is also a question of how well these baits work in humid areas and it has been suggested by some that they perform better in more arid regions.
Wine/Fermenting Fruit Bait. This sort of bait is basically an amalgamation of cheap red wine, sugar, and rotting fruit. You can use your imagination, as there are a million variations of this. We have had luck with strawberries and bannanas. Just mash the fruit up and mix it with the wine and sugar in a bucket and let it sit for a few days or more. The resulting mess is applied to tree trunks or to rope. The rope can actually soak in the solution and be pulled out and strung between trees in a forested type setting. Caution, you may want to use gloves, this stuff is messy. When putting this mix on tree trunks, the bait may be mixed more thickly, whereas the mix for the rope should be more of a liquid. This sort of bait is used for night collecting and is used primarily for the collection of certain moths, especially noctuiids. However, some other insects will be attracted to it as well including ants, some beetles, flies, orthopterans, etc.