Longicorn Beetles
Common Eucalypt Longicorn
Eucalypt Longicorn
Wasp-like Longicorn I
Wasp-like Longicorn II
Wasp-like Longicorn III 
Other Tribes
Large Brown Longicorn
One-banded Longicorn
Decora Longicorn
Flower Longicorn
Ant-mimicking Longicorn
Bamboo Tiger Longicorn
Lycid-mimicking Beetle
Fig Longicorn
Sheep Longicorn
Black Small Acacia Longicorn
Motley Small Acacia Longicorn
She-Oak Longicorn
Tea-tree Longicorn
Dark Brown Longicorn
Green Longicorn Beetle
Acacia Longicorn I
Acacia Longicorn II
Other Tribe 
Double-coned Longicorn 
Small Longicorn Beetle
Fern Longicorn Beetle
Unidentified Longicorn


Acacia Longicorn Beetle - Penthea solida


This page contains pictures and information about Acacia Longicorn Beetles that we found in the Brisbane area, Queensland, Australia.
Body length female 30mm, male 20mm
In mid summer, on those young Acacia trees in Mt Cotton, we found a few of those Longicorn Beetles. Some of them are actively moving around. When disturbed, some dropped onto the ground and played dead, some slowly flied away. 
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They appeared only in a short period of time in mid summer. A year later in the same area,  we easily found a lot of them.
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They have very long antennae, typically 11 segmented. They have obvious strong mandibles for chewing. Also notice its notched eyes and its antenna arising within the notch. This is the characteristic of all longicorn beetles.
On Dec 2008 we found them again on gum leaves. There were three resting on the stem. Two of them were mating. 
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Then we realized that the male and female are different size and colours. We found both of them individually and thought they were different species.  
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We found the male separately and thought they were different species.  
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Pictures were also taken in Karawatha Forest during mid summer.

Mimicking larger animal's face

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When looking at the beetle with the front view, we noticed why there are the round dome on each shoulder. Those domes mimic the eyes of a larger animal. The beetle spends long time on stem feeding plant skin. It will most likely encounter its predators, such as a bird, from above. The mimicking larger animal's face may scare away its predators. We have more information about face mimicking in this page.
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This Longicorn is quite common in Brisbane. 
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They were found on different species of Acacia
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1. Cerambycidae, subfamily Lamiinae - lifeunseen.com, by Nick Monaghan.
2. Specimen Image Index - Insect Reference Collection Database - ICDB, Western Australian Department of Agriculture. 

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Up ] She-Oak Longicorn ] Tea-tree Longicorn ] Dark Brown Longicorn ] Green Longicorn ] [ Acacia LongicornI I ] Acacia Longicorn Beetle II ]


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Last updated: March 10, 2012.