Leaf litter collecting in etesian dry habitats

An exchange with Roman Borovec

In February 2022, while corresponding with Roman Borovec on several weevil topics, we got to discussing his unique methodology for collecting weevils in dry leaf litter and my possible attempt at his method during my upcoming visit to California. He and Massimo Meregalli had just presented on this topic during the 2021 Online Weevil Meeting. They discussed their leaf littler sifting technique used in South Africa and I wanted to find out more.  I asked, and Roman agreed, to allow me to share part of our correspondence as well as some of his amazing photographs of the weevils collected using this technique. I hope you find this information as useful as I did. Thanks Roman!

– Lourdes Chamorro

“The strip around the coast in California is one from I think five areas (so called etesian type of vegetation) in the world with similar climatic conditions and also similar plant associations. Sifting in areas with this kind of vegetation has two conditions – to collect weevils and to sort them from the soil. Collection means sifting under either small plants or under bigger bushes. Sifting under small plants - I sift either under known host plants of weevils, or under perennial plants mainly forming “cushions”, as for example Thymus, Potentilla, Fragaria and others here, or rosettes of large leafs as Verbascum, Cirsium and others. Entimines (but most likely also cyclomines) are polyphagous, searching more for suitable hiding places than for specific plant species. I sift to about 3-4 cm in depth, with all soil and litter below the plants, and if possible also with roots. You can also pull out the entire plant with roots and beat roots with soil to the sifter. It is very useful to stick a trowel under the plants, not to lose any falling material. Sifting under shrubs means to go under bigger shrubs forming good shadow and humidity and to sift all old dry leaves and dead branches with some soil below. In South Africa we use big shrubby Euphorbia, which is not very pleasant, but these big shrubs are very good shelter for weevils. Also shrubs of different Chenopodiaceae or Aizoaceae are very good place for sifting. Chenopodiaceae are often also very good host plant for many weevils.


To sort entimines is not as easy. Winkler or Berlese extractors are much better in partly wet forest litter, which is drying in time and weevils try to move and can fall down. Steppe, fynbos soil is completely dry, there is no drying out. First view we do just in the locality, under strong sunshine. If a plant has a thin layer of soil and the sun can light up and warm up the body of a weevil, they are also trying to move, slowly and slowly crawling and when they stop, you can not see them, because they start to be invisible having the same colour and structure as surrounding soil. But if one can see them moving, it is possible to find them. When we have success and we know they are in soil, we keep the soil in cloth small sacks and carefully search inside each morning and each evening. They are moving just on the surface of the soil and many times also on the surface of the sack, where one can discover them easily. They surely go up on plants at night, so in evening and morning collection in sacks corresponds with their life habit. Under strong sunshine I can collect several specimens, in sack of the same soil many more specimens during the next days. It is a successful method in these dry soil collections. Some of these sacks with soil I also bring with me to my working room in my house, and I am able to collect them even several months after the trip! from completely dry soil, where small spiders, ants and other beetles quickly died after several days. Edaphic entimines are able to survive many weeks in very dry conditions.


One must be really very patient for this kind of collecting. In the beginning it probably requires some experiences in choice of suitable place for sifting, but first interesting weevils are a very good motivation!”

Last updated October 31, 2022