Jacobus van der Vecht (5 July 1906 – 15 March 1992), nicknamed Jaap, was a Dutch entomologist who specialised in Hymenoptera, especially those of the East Indies and New Guinea.
His father, the Master of the Wine Cellars at the court of the then Queen Dowager of the Netherlands, Emma of Waldeck and Pyrmont, had an interest in natural history and reared butterflies as a hobby.
[1] After graduating Van der Vecht took a position in the Dutch East Indies at the Instituut voor Plantenziekten at Buitenzorg (the Institute for Plant Diseases and Pests at Bogor) in Java.
During this time he published work on the Indo-Australian Hymenopteran fauna including publications on Trigonalidae, Vespidae, Sphecidae, Apidae, Sapygidae and Pompilidae.
Another research project undertaken by him involved the rearing of 40 successive generations of the coconut leafmoth Artona catoxantha so that he could study its population dynamics, habits and the effect of parasites and hyperparasites.
Yet another research interest was the influence of climate on pests, publishing an important paper in collaboration with F. H. Schmidt on the fluctuation of the east monsoon in Java and Madura.
In addition, he discovered "Van der Vecht's gland", which is an organ which produces a secretion which some groups of vespids use to protect their nests from ants.
In January 1946 he went home to The Netherlands to recover from his wartime experiences and he also spent three months in the USA, so that he could study the latest developments of agricultural entomology.
[1] In 1947 he returned to Java to take up the position of head of the Institute for Plant Diseases and Pests at Bogor and here he cared for the important collection of insects.
He was energetic in helping to improve the collection of Hymenoptera in the Rijksmuseum van Natuurlijke Historie at Leiden as well as continuing to publish papers into his eighties.