1. DISTRIBUTION

Issus coleoptratus ^{[Soortenregister]} is a common species in the Netherlands ^{[Waarneming.nl]}.

2. BEHAVIOUR

2.1. ACTIVITY

The nymph instars 2 to 4 probably overwinter, possibly instar 5 as well ^{[Whitehead & Key 2010]}. Adults appear in May and can be found until November ^{[Whitehead & Key 2010]}.

As a side note these animals cannot fly but instead hop.

2.2. DEVELOPMENT

It is still unclear whether the species produces one or more generation each year and whether the development follows an irregular pattern. This is apparent from the different nymph stages that can be found simultaneously ^{[Whitehead & Key 2010]}.

2.2. FOOD

These cicadids feed on phloem, cells on the inside of the bark that transport the nutrients in the tree, from different tree species like:

• Tilia
• Oak
• Maple
• Birch
• Elm
• Common hazel

2.3. DEFENSE MECHANISM

The light blue-ish filaments at the end of the abdominal tip are made of wax that is secreted from glands. The purpose is possibly related to defence against parasites and predators as those will attack the threads which gives the nymph an opportunity to flee ^{[Resh & Cardé 2009]}. These waxy structures are a well known characteristic in many cicadid nymphs ^{[Hamilton 2011]}.

3. IDENTIFICATION

3.1. LARVAE

The larvae, nymphs, of the genus Issus can be identified by ^{[Zenner 2005]}:

1. Postclypeus (part of the lower half face) lies below the eyes
2. Vertical keels on face (frons)
3. Vertex less than twice longer than wide

In the Netherlands exist two species from this genus,  I. coleoptratus and  I. muscaeformis. The nymphs of both species resemble a lot but can be distinguished based on the following characteristics:

1. Frons I. coleoptratus has a medial horizontally light colored banding  instead of a dark ^{[Zenner 2005]}
2. The sensory pits in the frontwing pad are in I. coleoptratus large, clearly articulated and typically in a group of 10, instead of smaller, less clearly separated pits in a typical grouping of 7 ^{[Zenner 2005]}.

This specimen is a 5^th instar which can be determined based on the development of forewing pad, of which the tip reaches up to the base of Tergite III.

3.2. ADULTS

The adults have a disc-like spot on the forewing ^{[Zenner 2005]}.

In frontal view the species has a clear dark zone directly beneath the vertex ^{[Zenner 2005]}, the top side of the head.

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Literature

^{Hamilton 2011} Hamilton, K. A., 2011. Making sense of Fulgoroidea (Hemiptera): new phylogenetic evidence. Cicadina, 12, 57-79.

^{Resh & Cardé 2009} Resh, V. H., & Cardé, R. T. (Eds.)., 2009. Encyclopedia of insects. Academic press.

^{Soortenregister} Nederlands Soortenregister

^{Waarneming.nl} Waarneming.nl

^{Whitehead & Key 2010} Whitehead, P. F., & Key, R. S., 2010. Observations on British Issus (Hemiptera, Issidae) with reference to development, periodicity and ecology. Worcestershire Record, 29, 22-27.

^{Zenner et al. 2005} Zenner, G., Stöckmann, M., & Niedringhaus, R., 2005. Preliminary key to the nymphs of the families and subfamilies of the German Auchenorrhyncha fauna:(Hemiptera, Fulgoromorpha et Cicadomorpha). Cicadina, 8, 59-78.

Citation

Krischan, O.R., 2025. Issus coleoptratus. Kerfdier, www.kerfdier.nl. Accessed on 13 May 2025.