©The British Tarantula Society Study Group
A Study on the Breeding Behaviour of Baboon Spiders
Mike Jope

A Comparative Study of the Mating Behaviour of Baboon Spiders, or African theraphosid spiders and the relationship between specie

The following study involves a number of species of theraphosid spiders also known as tarantulas or baboon spiders, kept by myself over a number of years.  I have listed observations on a number of pairings of three African genera, Ceratogyrus, Pterinochilus and Hysterocrates. Ceratogyrus and Pterinochilus are both closely related members of the Harpactirinae sub-family, with Hysterocrates being grouped under the Eumenophorinae sub-family.  All old world theraphosids lack the urticating hairs, which are a feature of most new world species.

The genera Ceratogyrus and Pterinochilus come from sub-Saharan Africa and generally come from dry grassland and scrub, where they live in burrows thickly lined with silk to combat desiccation.  They have similar coloration, either sandy yellow or greyish brown and tend to be small to medium by theraphosid spider standards, the largest species reaching perhaps 150 mm in leg span.  The males of the species are often considerably smaller than the females.  Most theraphosids make egg sacs that are carried by the female, unusually both these genera make egg sacs that are built into their webs, and then guarded by the female.

Ceratogyrus species are usually known as horned baboon spiders, as they have a projection from the fovea in the middle of the carapace, sometimes in the shape of a horn, used to store a food reserve.  The foveal horn of Ceratogyrus is a very useful identification feature, being different for each species, varying from a plug to a long keel or erect horn.  Foveal horns also have the useful advantage that specimens can be easily sexed several moults from adulthood as the foveal horns of male and female are sexually dimorphic.

The usual name for Pterinochilus species in captivity is starburst baboon spiders.  This name being derived from the radiating pattern extending from the fovea to the outer edge of the carapace.  Both these genera tend to be very aggressive and will rear up and bare their fangs when disturbed, striking and making a hissing sound by stridulation between their palps and chelicerae.  The males in Pterinochilus can be remarkably small, as little as a third of the female’s leg span, although about two thirds is probably more usual.

The genus Hysterocrates comes from West Africa and generally lives in forested areas where they construct very deep and complex burrows.  The females have enlarged hind legs adapted for burrowing.  Hysterocrates produce paper like, spherical egg sacs that are carried by the female during incubation.  These egg sacs usually fail to hatch if removed from the female too soon.  They include the largest African spider species, Hysterocrates hercules, the Hercules Baboon spider, which grows to over 250 mm in leg span.  Unusually female H. hercules do not have the enlarged rear legs found in most other Hysterocrates species.  The Hercules baboon spider is larger than the related King baboon, Citharischius crawshayi, that is sometimes quoted as the larger species of the two.

The identification of Hysterocrates species tends to be difficult by sight as most species are dark brown and large, measuring from about 140 mm to 250 mm in leg span.  In both sexes the coloration fades rapidly following a moult.  The males of Hysterocrates tend to be smaller than the females, generally about two thirds their leg span, and without the stout hind legs that are characteristic of the genus.  Males are often sexually dimorphic in colour, having completely different coloration to their female’s.  This feature is not uncommon amongst theraphosids.

The species involved in this study were Ceratogyrus cornuatus, C. darlingi, Pterinochilus lugardi, P. meridionalis, P. murinus, P. sjostedti and Hysterocrates gigas.  For convenience the notes for each species will be listed under their scientific name and comparisons will be made after.  Some success was had in breeding them and the relevant notes will also be included as a point of interest.  The specimens were kept in a heated room at a temperature of 24 ºC using a large electric chimney heater controlled by a thermostat.  Photographic records were also kept of the matings and exerts of these will also be used to provide illustrations to accompany the breeding notes.

Theraphosids, like all other spiders, have a comparatively unusual form of mating behaviour that requires a basic explanation.  When the male theraphosid matures he waits anything from 1 to 6 weeks and then goes in search of a mate.  Male spiders have their sexual organs on the ends of their palps, known as palpal bulbs.  They fill them with sperm by building a special web, laying a droplet of sperm on it and then crawling underneath and filling their palpal bulbs one at a time.  They then destroy their sperm web and are ready to find a mate.

The male wanders until he finds a female, he then courts her and if she is receptive he will mate with her.  If she is unreceptive he will reluctantly make his escape and move on to find another female.  When he finds a receptive female he will get her to rear up and bare her fangs, when she does this he catches her fangs with hooks under his 1st pair of legs (Hysterocrates lack these tibial spurs).  He then inserts his palpal bulbs into her epigynum and injects sperm into the female’s sperm storage vessels (spermathecae).  He then makes a hasty retreat, but occasionally he is pursued by or cannibalised by an angry female.  The female stores the sperm in her spermathecae until she needs it to fertilise her ova during the production of her egg sac.

Pterinochilus murinus mating (G in foreground)

Hysterocrates gigasPocock, 1897                  JIHDE X MKG              (#1)

Giant Cameroon baboon spider
Breeding notes

 29/06/96 Three spiderlings obtained from Joe’s invertebrate house.

16/01/98 Hysterocrates gigas JIHDE moulted measuring approximately 140mm in leg span.

30/07/98 JIHDE moulted.

08/09/98 JIHDE mated with Mark Kent’s male (MKG) (matured approximately 15/08/98), about an hour after he arrived in the post he seemed to be going through a courting ritual, walking slowly and carefully with his legs extended and occasionally vibrating his palps.  When transferring him into her tank by encouraging him to move with 12 inch forceps he struck at the forceps before moving into her tank.  Within a minute of being introduced he paired with her the first time, rapidly vibrating his body, before pushing himself underneath her.  He mated with her by reaching around her pedicel or waist and inserting his palps.  With her abdomen raised vertically, she made a token attempt to bite him. Within a further minute he approached her a second time, vibrating his body, and lightly tapping her legs with his front legs and paired with her again.  After this he pursued her and she backed away before she crouched down against the substrate and refused to allow him to mate a third time.  After about 15 minutes of him vibrating and tapping her body and legs with his front legs he moved away.  She then retreated down one of her shallow burrow holes.

18/02/99 JIHDE laid her egg sac, one day after her vermiculite substrate was changed to peat.

10/04/99 Egg sac hatched.

16/04/99 JIHDE was removed in case she cannibalised the spiderlings, at the time of writing (20/04/99) only 8 have been seen, but checking the substrate indicated there were many more hiding in the substrate.

22/05/99 Caught the last few spiderlings from the brood.  Total number of spiderlings 159, of which 22 had died at the time of writing.

11/08/99 JIHDE had her annual moult.

30/01/2000 JIHDE has been drumming on the side of her container trying to attract a male.

16/04/2000 JIHDE was found dead, there was no smell, no shrivelling of the abdomen, she didn’t seem undernourished and there were no mites and she had no injuries, possibly natural causes?

FEMALE MOULT CYCLE 371 DAYS.

FEMALE FERTILE AT 38 DAYS AFTER HER ANNUAL MOULT.

GESTATION 160 DAYS (possibly retarded by unsuitable substrate).

INCUBATION 52 DAYS.

Hysterocrates gigasPocock, 1897                  PLE X MKG                 (#2)

Giant Cameroon baboon spider

Breeding notes

Wild caught, 175mm leg span female Hysterocrates gigas (PLE) was purchased as a king baboon.

20/07/98 PLE has annual moult.

19/09/98 Mated male Hysterocrates gigas MKGwith PLE.  She drummed her willingness to mate, but he was shy of her.  They paired twice again, once with each palp, and he fled after the second pairing, leaping up onto the side of the tank.

07/01/99 PLE found to have an egg sac.

07/02/99 PLE threw out her empty egg sac.  When her retreat was checked it was found to contain spiderlings.

14/02/99 65 spiderlings separated off.  After an hour additional spiderlings were recovered from the side of the glass tank making the grand total 293.

02/05/99 PLE had her annual moult.

FEMALE MOULT CYCLE 282 DAYS.

GESTATION 108 DAYS.

INCUBATION 30 DAYS.

BROOD 293.

Hysterocrates gigasPocock, 1897                  WC’E’ X DJG               (#3)

Giant Cameroon baboon spider

Breeding notes

11/02/2000 Obtained an adult ‘E’ Hysterocrates gigas (WCE) from 2x2.

02/03/2000 Tried pairing WCE with a male sent by Dave James (DJG).  ‘She’ was receptive, but moulted into an adult male two days later (04/03/2000).

Hysterocrates gigasPocock, 1897                  PLE X DJG                  (#4)

Giant Cameroon baboon spider

Breeding notes

01/03/2000 Received an adult male Hysterocrates gigas (DJG) from Dave James (same specimen as mentioned above).

04/03/2000 Mated PLE with DJG.  She was receptive and allowed him to try to mate, but when he tried to insert his palps he panicked and ran rapidly away.

04/04/2000 PLE laid an egg sac.

08/05/2000 Egg sac was taken from PLE.  She resisted strongly and it took ten minutes to get her to finally let go of it by rolling a pencil underneath her fangs whilst using a pair of 12 inch forceps.  A small hole was cut in the egg sac and a postembryo was seen to move its legs.

11/05/2000 Six postembryoes have now left the egg sac, possibly by accidentally falling out of the hole rather than emerging.  The egg sac is being kept in a absorbent, kitchen paper lined box that is humidified 2 or 3 times a day by dropping 6 drops of water on the kitchen paper towel lining away from the egg sac.

20/05/2000 12 postembryoes have now left the egg sac.

24/05/2000 About half of the postembryoes have left the egg sac.

25/05/2000 All postembryoes have emerged and have darkened.

27/05/2000 Two postembryoes moult into spiderlings.

28/05/2000  All postembryoes have moulted into spiderlings.  261 in total.

GESTATION 30 DAYS.

INCUBATION TO POSTEMBRYOES 37 DAYS.

Hysterocrates gigasPocock, 1897                  PLE X WCG, RGG       (#5)

Giant Cameroon baboon spider

Breeding notes

16/05/2000 Paired Hysterocrates gigas PLE with WCG (see #3).  The pairing seemed to go as usual, with the male pairing with her twice in 10 minutes.  She showed no aggression towards him.

29/05/2000 Mated Hysterocrates gigas PLE with male from Ray Gabriel (RGG).  The male stridulated and raised up vertically when moved from his holding container.  When introduced to the female’s tank he entered her retreat and mated with her within a minute of being introduced, apparently using both palps.  He then sat still for about 5 minutes before approaching her again.  He vibrated his body a little as he re-entered her retreat.  She slowly pursued him back out of her retreat and arched over him, encompassing him with her legs.  When he attempted to mate with her a second time she overpowered and killed him, biting him between his fangs and the trochanter of leg I, she then ate him.

09/08/2000 PLE produces an egg sac

Ceratogyrus cornuatusDe Wet & Dippenaar-Schoeman, 1991    

Zimbabwe rhino horned baboon spider                       BE X CG, DJG, RLG    (#6)

Breeding notes

27/07/99 Ceratogyrus cornuatus CG matured, completing a pair.  Note that Ceratogyrus can be easily sexed by comparing their foveal horns, the males being much smaller than the females from juvenile.

08/08/99 Attempted pairing BE and CG.  She approached him tapping her front legs on the substrate every few seconds, but he refused pairing and was removed to try later (assumed that the male was too recently matured for a mating attempt).

14/08/99 Mated BE and CG again.  The male was extremely aggressive, striking repeatedly at the 12 inch forceps and hissing when he was encouraged to move into her tank.  After he had been encouraged into entering her tank she walked over towards him, tapping her two front legs on the substrate every inch or so.  When she touched him she jumped back about 8 inches and went into an impressive threat display, rearing up almost vertically and showing the black underside of her upper front legs and body.  After a minute or so she stopped threat displaying and went carefully over to him.  When she touched one of his front legs he lifted his palps up vertically and held his front pairs of legs up and outwards to make himself seem as large as possible.  She tapped on his front pair of legs for about 20 seconds and he caught her fangs with his tibial spurs and mated with her.  The insemination was very brief, lasting about 2 seconds.  Afterwards he retreated about 4 inches and started to preen himself, she rubbed her epigynum with her legs (indicative of a successful pairing), and retreated to the other corner of the tank where she vigorously groomed herself.  He was removed and put back in his own tank.

28/10/99 Adult male C. cornuatus received from Dave James (DJG).

31/10/99 Mated BE with DJG. The mating was identical to that observed between the specimens on the 14/8/99.

01/03/2000 Received another male from Roy Laurie (RLG).

04/03/2000 Tried mating RLG with BE, but he fled from her, probably sensing she was gravid.

19/06/2000 BE moults.

Ceratogyrus darlingiPocock, 1897                 EE X DG                       (#7)

Mozambique horned baboon spider

Breeding notes

17/06/97 Ceratogyrus darlingi EE moults.

18/06/97 DG completes his maturing moult.

02/07/97 DG made a sperm web (probably his first).

19/07/97 EE mated with DG.

24/07/97 DG made sperm web.

23/08/97 EE laid her first egg sac, which was very large for her size and fixed at a slope across one corner of her tank.  After laying she guarded it until disturbed by a TV. crew.

15/09/97EE consumed her egg sac after being disturbed by the TV. crew, her tank was knocked by a TV. camera and their lights probably disturbed her as well.

20/09/97 DG died.

09/10/97 EE moulted, only 4 months since maturing.  Note she was mated and laid an egg sac, so she was definitely adult.

MALE FERTILE AT 31 DAYS AFTER MATURING, LIVED FOR 92 DAYS.

GESTATION 34 DAYS.

FEMALE MOULT CYCLE 112 DAYS.

Pterinochilus lugardiPocock, 1900                RGE X DJG                  (#8)

Kwebe mustard baboon spider

Breeding notes

Adult female obtained from Ray Gabriel (RGE).

29/12/99 Tried pairing Pterinochilus lugardi RGEand DJG.  The female was receptive, but the male was only interested in escaping, having run over her twice and having been huddled up against her, its probably to early for him since he matured.

08/01/2000 Mated RGE with DJG.  It was a very slow mating for a Pterinochilus species taking over 45 minutes and he had to annoy her into letting him mate.  She tapped her palps briefly against the side of the tank twice when she detected him approaching.  He climbed up on to her body from behind and sat there for about 10 minutes, during which she was pressed against the corner of the tank with her abdomen against the substrate.  He then tried to get round her from the side and after several more minutes she turned a little to face him.  He then attempted to mate with her and for 10 to 15 minutes she was held with her body pushed back vertically by him, with him vibrating his body for 30 seconds at a time to try and make her receptive.  He then moved around and she tried to retreat.  He followed trying to climb up on to her abdomen again.  She turned and reared and he then managed to grasp her fangs and mate with her, pairing lasting several minutes, after which he retreated about 6 inches and started preening himself, he was removed and re-housed.

15/01/2000 RGE had her annual moult, one week after mating.

30/01/2000 Mated DJGwith RGE.  He encountered her cell as soon as he was introduced and remained stationary for 5 minutes.  He then started to court her, vibrating his front legs, and she reared up exposing her upper half.  After several minutes he coupled her fangs with his tibial spurs and mated with her. Insemination took an unusually long time, perhaps 5 minutes, during most of which his palpal bulbs were inserted in her epigynum.  After he removed his palpal bulbs he retreated and drunk from the water bowl whilst she remained motionless in the mating posture for a further 5 minutes.  She then advanced towards him and he retreated.

14/07/2000 RGE dies.

NO EGG SAC 164 DAYS LATER.

Pterinochilus meridionalisHirst, 1907                   BWE X DJ1G, DJ2G   (#9)

Zambian grey starburst  baboon  spider

Breeding notes

Female obtained from Bert Wander (BWE).

28/10/99 Received an adult male from Dave James (DJ1G).

31/10/99 The very small DJ1Gwas put in with BWE.  He tried to mate with her 3 times although she was receptive he may have been too small as he could not reach her epigynum.  He was removed from her tank late the same evening.

06/01/2000 BWE produced a silk ‘L’ shaped tunnel with a cell at the corner (as she is mated could be either for egg sac laying or moulting).

01/03/2000 Received  a second adult male Pterinochilus meridionalis (DJ2G) from Dave James.

04/03/2000 Mated BWEwith the small DJ1G.  She was receptive and left her cell to mate with him.  He should have been able to reach her epigynum this time.

11/03/2000 Put DJ2G in with BWE.

18/03/2000 Removed DJ2G from BWE tank after a week.

Pterinochilus murinusPocock, 1897             RG1E X RGG               (#10)

Golden starburst baboon spider

Breeding notes

14/04/99 RGG completes maturing moult.

17/04/99 RG1E moulted completing a breeding pair.

24/04/99 A very large male Pterinochilus murinus RGG was left in overnight with the RG1E.

30/05/99 RG1E moulted again.

06/06/99 RGG and RG1E were put in the breeding tank and left together for several days.

10/07/99 RG1E laid her egg sac, building it against one side of her sweet jar.  She finished building it on the 11/07/99 and has been guarding it since.

16/07/99 RG1E is still guarding her egg sac.

04/08/99 Egg sac hatched, 18 postembryoes emerged.

05/08/99A hole was cut in the top of the egg sac in case any spiderlings were trapped.

06/08/99 41 postembryoes have emerged so far.

08/08/99 69 postembryoes have emerged and seem more mobile than when they first emerged.

15/08/99 The postembryoes have all darkened.

17/08/99 Postembryoes started moulting into spiderlings.

18/08/99 21 spiderlings were individually housed.

28/10/99 RG1E was found to have laid a second rather small egg sac.

12/11/99 The second egg sac was taken from RG1E and the young were found to be undeveloped.  They turned out to be a little slower to develop than the first brood.

24/11/99 Pterinochilus murinus second brood RG1E emerged as postembryoes (49 present).

14/07/2000 RG1E dies at about two years of age.

GESTATION 76 DAYS, THEN AN ADDITIONAL 108 DAYS FOR THE SECOND EGG SAC.

INCUBATION 24 DAYS (FIRST EGG SAC), 26 DAYS (SECOND EGG SAC).

FIRST BROOD POSTEMBRYO TO SPIDERLING 13 DAYS.

FIRST BROOD 98 & 12 INFERTILE OVA.

Pterinochilus murinusPocock, 1897             RG2E X JRG                (#11)

Golden starburst baboon spider

Breeding notes

16/07/99 RG2E moulted.

01/10/99 Jim Randal’s Pterinochilus murinus male matured (JRG).

16/10/99 Mated RG2E with JRG.  He mated with her, interestingly he became very excited on contact with her and circled around her with his front legs on top of her as in the P. sjostedti matings.  After he mated with her she pounced on him, killing him before he had chance to escape.

28/10/99 RG2E has put down an extremely large egg sac laying carpet.

03/11/99 RG2E has completed her extremely large egg sac.

05/12/99 RG2E brood emerged, probably in excess of 200 young.

09/12/99 P. murinus brood started moulting into spiderlings, eventually totalling 219.

16/07/2000 RG2E dies at about two years of age (NB. sister RG1E died two days earlier).

MALE FERTILE 15 DAYS AFTER MATURING.

GESTATION 12 DAYS.

INCUBATION 37 DAYS.

POSTEMBRYO TO SPIDERLING 4 DAYS.

BROOD 219.

Pterinochilus sjostedtiTullgren, 1910            RGE X DJG                  (#12)

KILIMANJARO BABOON SPIDER

Breeding notes

10/07/99 Obtained an adult female from Ray Gabriel (RGE).

14/07/99 Mated RGE with DJG.  When he was introduced to the female’s tank he first sat on the side, occasionally vibrating his body.  As soon as he realised the female was present he approached her and drummed on her legs and body.  He began circling her rapidly and became so excited that he spiralling outward and lost contact with her.  She vibrated her body to help him locate her and after more excited drumming by him and body vibrating by her they mated, the pairing taking several minutes.

25/08/99 RGE laid her egg sac.  As it is laid between thick horizontal sheets of silk in the nest it is not very apparent.  She is sat on top of it guarding it.

14/09/99 Opened the egg sac, postembryos were present, but were not well-developed. DJE postembryoes seem more active and quicker moving.

18/09/99 RGE brood started emerging.  Four postembryoes having emerged.

19/09/99 47 postembryoes have emerged so far from the RGE egg sac.

21/09/99 About 90 postembryoes have now emerged.

07/10/99 RGE postembryoes have moulted into mobile spiderlings (about 120).

14/10/99 RGE has her annual moult.

GESTATION 41 DAYS (possibly slowed by desiccation, causing her to delay egg sac laying).

INCUBATION 23 DAYS.

Pterinochilus sjostedtiTullgren, 1910            DJE X DJG                  (#13)

KILIMANJARO BABOON SPIDER

Breeding notes

10/07/99 Obtained an adult female from Dave James (DJE).

22/07/99 DJE mated with DJG.  The mating went exactly as with the previous one, with the male excitedly circling the female, and the female vibrating her body up and down to signal her receptiveness.  Being a small female, she fell backwards during mating and pursued him angrily afterwards.

11/08/99 DJE has made what appears to be an egg sac laying bowl, unfortunately the silk seems very coarse, so the humidity was increased by adding a few drops of water in one corner of the tank.

20/08/99 DJE laid her egg sac, and is sat on top of it guarding it.

26/08/99 Pterinochilus species build their egg sacs into their web so DJE was removed from her egg sac to eliminate the risk of her consuming it.

10/09/99 Opened up the egg sac, postembryoes were found to be present.

11/09/99 About 20 postembryoes have emerged from DJE egg sac, with a large number still remaining within the egg sac.

12/09/99 58 postembryoes seen on the egg sac.

14/09/99 Postembryoes seem active and quick moving.

18/09/99 Postembryoes mobile and highly nervous, most choosing to sit at the top of the incubation web underneath the lid of the tank.  When the tank is disturbed they all run back down and cluster in the egg sac and sheets of web.  About 90 seen so far.

28/09/99 Pterinochilus sjostedti brood moulted into fully mobile spiderlings.

16/10/99 Spiderlings started feeding on 2nd-3rd instar house crickets.

09/01/2000 DJE had her annual moult.

GESTATION 28 DAYS.

INCUBATION 21 DAYS TO POSTEMBRYO, PLUS AN ADDITIONAL 17 DAYS TO SPIDERLING.  38  DAYS FROM EGG SAC LAYING TO SPIDERLINGS.

BROOD APROXIMATELY 100.

Pterinochilus sjostedti E guarding egg sac

Pterinochilus sjostedti postembryoes (darkened & ready to moult)

SUMMARY TABLE OF THERAPHOSID MATINGS

* G killed during mating

† Second egg sac between E moult

THE GENUS HYSTEROCRATES

There are no comparative data for breeding the genus Hysterocrates available, so conclusions have been drawn from my own data.  The courtship of Hysterocrates seems to be mostly down to the male, with the female occasionally drumming on the side of her tank when she is receptive.  Even a sub adult male may be tolerant to pairing.  The female seems to refuse mating by crouching down on the ground so the male can not use his palps.  If she is receptive he mates with her twice over about 10 minutes, she then crouches down on the ground to refuse any further pairing.  After a further 15 minutes he usually gives up any further attempts to mate and leaves in search of another female.  The usual gestation of Hysterocrates would seem to be about 3.5 months, with incubation taking about 7 weeks for the spiderlings to emerge.  An egg sac taken from the female and opened at 34 days into incubation was found to contain mobile postembryoes.  The average brood size is just over 200 spiderlings.  It was discovered that H. gigas females are able two produce two egg sacs between annual moults.

THE GENUS CERATOGYRUS

The genus Ceratogyrus contains the horned baboon spiders.  These are small to medium sized species closely related to Pterinochilus, but have a projection protruding from the carapace. The foveal horns are in the centre of the muscle attachment of the legs.  Theories vary, but currently it is thought that the horn acts as a fat reserve.  Ceratogyrus cornuatus is known as the rhino horned baboon spider and come from Zimbabwe.  They are named after the large vertical horn of the female, but the male’s horn is a small, slightly raised wedge.   Males and females both have leg spans of about 120mm.

The male was unwilling to mate 11 days after maturing and was paired a week later with the extremely aggressive female.  The female approached him and on contact reared up vertically.  She then approached him and he held his front legs up and outwards to seem as large as possible.  After tapping each others legs for a minute or so he caught her fangs with his tibial spurs and mated with her.  Insemination was extremely quick, perhaps taking 2 seconds.  A mating with another male 11 weeks later was behaviourally identical.

Ceratogyrus darlingi is known as the Mozambique horned baboon.  Females measure about 120 mm in leg span and both sexes have a wedge shaped horn.  Males are smaller at 90-100 mm.  They are fairly short lived by theraphosid standards, males living about 3 months after maturing.  I had my female and male mature within 1 day of each other by selective feeding, but it is probably more usual for males to take 18-24 months and females 30-36 months to mature (Gurley 1995).

The male made his first sperm web 14 days after maturing, with another one 22 days later.  They were paired 31 days into maturity and she laid her egg sac 34 days later.  Unfortunately she cannibalised her egg sac after being disturbed.  Ezendam (1997) described the breeding of C. darlingi giving the gestation period as 137 days, incubation to postembryo 38 days with an additional 19 days for the postembryoes to moult into spiderlings.  Ezendam approximated the brood size at about 175.  In the wild the spiderlings are stated to emerge at the beginning of the dry season (Hancock 1992).  Ceratogyrus bechuanicus is very similar to C. darlingi and often confused with it.  It is stated as having a gestation of 5 to 6 weeks and an incubation of 3 to 5 weeks and broods of approximately 130 that moult into spiderlings 10 to 14 days later (Baxter 1993).  This closely parallels the majority of Pterinochilus species.

THE GENUS PTERINOCHILUS

Pterinochilus murinus is known as the Kenyan golden starburst baboon, and is the most common species of Pterinochilus in captivity.  Females can reach 140 mm in leg span and will breed from about 80 mm span.  The males are generally smaller than the females.  It breeds easily in captivity (Baxter 1993; Gurley 1994) and is extremely protective of its egg sacs and young.  Females can produce up to 3 egg sacs from a pairing at intervals of about 2 months (Hancock 1992).

The male’s courtship involves him circling her, tapping her with his front legs.  One male was killed and eaten immediately after mating by a very large female.  The cannibalisation of the male is not unusual, 1 in 3 of my pairings resulted in this, and cannibalisation of males is stated as happening often after mating (Gurley 1994).  Having said this, males and females have also been stated to live together happily until the egg sac hatches (Hancock 1992).  Males take around 12 months to mature and females live for about 4 years (Hancock 1992).  Males are fertile from 2 to 7 weeks after maturing.

Gestation periods vary, my own specimen’s gestation being 76 days with a 2nd egg sac 108 days later and just 12 days gestation for my larger specimen.  The young of Pterinochilus emerge from the egg sac as postembryoes, a non feeding halfway stage between fully mobile spiderlings and ova, and are guarded by their mother until they moult.

Incubation takes 3 to 4 weeks (Baxter 1993 quoting 3 weeks), with an additional 1 to 2 weeks for the postembryoes to moult and become independent.  Brood size varies, my smaller female producing 98 spiderlings then 50 from the second egg sac.  My larger female produced 219 spiderlings.  Reported broods include 75 (Reger 1995) and 75-150 (Gurley 1994).

Pterinochilus meridionalis is a large, greyish brown species from Central Africa.  Females reach 130 mm in leg span and males average around 80 mm.  Females are usually receptive, emerging from their nests to mate.  Males can be left with the female for at least a week without loss.  Their courtship is quite long and females are receptive to small males.  A very small male (60mm leg span) was allowed to mate, but was too small to hold her fangs and reach her epigynum.  After the third attempt she withdrew to her nest again without attempting to attack him.

Pterinochilus murinus (red colour form), the orange starburst baboon is another East African taxa.  It is said to be easy to breed, with a life cycle similar to P. murinus (typical colour form) (Gurley 1995).

Pterinochilus sjostedti is a smaller, stockier species, measuring about 75mm leg span.  It is found around Mt Killimanjaro in Tanzania.  Males and females are similar in coloration, but the males are slightly smaller.  The male courts the female by vibrating his body and drumming on her with his palps.  A receptive female vibrates her body to show she is receptive and mating is quite quick, taking about 5 minutes.  Gestation takes between 4 and 5 weeks, with the incubation taking a further 3 weeks for the postembryoes to emerge.  These cluster on the mother’s web, moulting into mobile spiderlings about 2 weeks later, then disperse.

Pterinochilus lugardi (incorrectly labelled as Harpactira curvipes in Gurley 1994), is one of the smaller species of Pterinochilus with a leg span of about 80 mm.  Males and females are of similar size.  It comes from dry grassland areas in the Kwebe hills of southern Africa.  It is one of the most docile members of the Pterinochilus genus.  The male refused to pair at 2 weeks into maturity, mating with her a week later.  The pairing was unusually long at 45 minutes.  She moulted 7 days after mating and was paired 15 days after her annual moult.   The second mating taking about 20 minutes.  On both occasions she was not aggressive towards the male.