Huntsman egg incubation

Huntsman spider egg sacs are among the largest of Australian spiders and it can be surprising that all the little spiders can tolerate each other as they do.

Huntsmen lay eggs within an egg sac. They secure the egg sac under loose tree bark and stay with their eggs until they hatch. The slings hatch after a month or two, and hundreds of spiderlings may emerge from a single egg sac. The spiderlings cluster around the mother for a week or two after they emerge and don't eat each other at this stage. Once they leave, if the slings find each other, this usually results in cannibalism.

Each different species has a different reproduction trend (amount of eggs, gestation period, incubation period and time spent with the mother.

(Fig.1) Giant banded huntsman (Holconia immanis) mother guarding her eggs.

(Fig.2) Grey huntsman (Isopeda vasta) mother and eggs inside silk retreat.

(Fig.4) Grey huntsman from Fig.2 just before laying eggs

As seen in fig.1, the giant banded huntsman eggs have developed to the point which they are slightly visible through the egg sac as little bumps.

The eggs can be monitored throughout the incubation process in this case by shining a reasonably bright torch through the eggs, the torch on a smartphone is optimal as its not too bright to scare the mother.

Some huntsmen make a nest to guard their eggs such as in this grey huntsman in Fig.2. if it was available, the mother would have incorporated leaves and bark pieces into the retreat.

There are many species of huntsman that have difficult egg incubation with the mothers eating the eggs, even while their viable. Lots of Theraposid species do this with disturbances or fluctuations in temperatures but no one has really determined why this happens and why they do it so readily. green bellied huntsmen, Giraween grey huntsmen/binnaburra grey huntsman, cave huntsmen/giant rock huntsmen and tiger huntsmen are all species that have been observed to without much reason eat their eggs.

Fig.1

Huntsman eggs can be incubated externaly which is best done for the species that tend to eat their eggs more. In most cases, the eggs can be grabbed right off the huntsman right after their laid for best results but if things tend to lead south for the mother eg, starving, enclosures not suitable, they can be taken later in the incubation process.

Fig.1) Green bellied huntsman (Typostola barbata) eggs. These were laid 3-7-22 and the photo was taken 11-7-22. This species lays giant egg sacs, sometimes reaching 50mm diameter. Green bellied huntsmen are one of the species that eat their eggs more often so externally incubating is best.

Fig.2) Giant banded huntsman (Holconia immanis) "eggs with legs". Eggs with legs is a term commonly used by breeders to tell the first stage of growth in spiders. This egg sac has been opened due to how far the incubation process has been so when the spiders moult again to slings/first instar they can get out without being trapped.

Fig.2

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