Besides plants, what type of organism did Mendel also study?

Besides plants, Mendel also studied honeybees.

Mendel’s best-known work involved pea plants, but his interests extended to animal breeding and heredity. At the Augustinian monastery in Brno, he kept bees in specially designed hives and worked with different honeybee varieties, including Cyprian and Carniolan bees. An apiary was built in the monastery garden in 1871.

His bee work was much less successful as a scientific record than his pea experiments. The bees were notably aggressive, causing difficulties for other monks and visitors, and Mendel was eventually asked to remove them. Most of his experimental results did not survive; the remaining evidence comes largely from brief references in reports of the Moravian Apiculture Society.

This is why honeybees can be overlooked in accounts of Mendel’s research. Fruit flies became famous in genetics through later researchers, especially Thomas Hunt Morgan, while Mendel’s own landmark inheritance experiments used peas. His bee studies nevertheless show that he was interested in heredity beyond plants.