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Old House Borer Larva
The head of the
old house borer larva is round and is much larger than its tail, a shape which
is typical of the Cerambycidae beetles which are known as "round headed borers."
This larva is greyish-white in colour and grows from 2 cm to 4 cm in length.
Female larva is significantly larger than male larva of the same age. The head
capsule is dark brown, and three simple eyes are found on each side of the head
when viewed from the front. This characteristic sets the old house borer larvae
apart from other long horned beetle larvae found infesting wood. Other long
horned beetle larva has only one such eye on each side of the head. The holes of
the larvae are oval shaped. The frass of the old house borer consists of very
fine powder and tiny pellets that are tightly packed within the galleries or
hols. |
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Wood consumption
in all larval weight classes was greatest in the temperature range of 20°C to
30°C, and significantly reduced below and above these temperatures. Inside that
temperature range, larvae consumption of wood is greatest at higher temperature
and higher relative humidity with less vary. Larvae consumption of wood in ideal
environment conditions (29°C ±2°C, 80 ±5% RH) is about 34 mg/larva per day, but
significantly low at still very good environment conditions with greater
deviations (24°C ±10°C, 76 ±9% RH), only about 12 mg/larva per day.
Despite a significant difference between larvae weights they consume nearly the
same amount of wood. |
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Developmental
rates of Hylotrupes bajulus larvae are affected by extremes of temperature;
medium and large larvae are affected to a greater extent by changes in
temperature than small larvae. Growth rates for small larvae were not
significantly different among temperatures while medium and large larvae
exhibited negative growth rates at 15°C and 35°C. The effects of temperature
were evident in low and high respiration values for medium and large larvae at
15°C and 35°C. Respiration rates were highest for small larvae. |
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In pine softwood
the activity is composed of single spurts, lasting from 5 to 180 min at a
relative humidity of 73%, alternating with phases of almost complete inactivity
lasting 5 to 25 min. They are getting more stable under temperature changes of
12 hours at 18°C and 12 hours at 25°C. |
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