More problems breeding C. crawshayi

More problems breeding C. crawshayi

or does a meat based diet cause egg development problems?

Introduction


Having successfully bred C. crawshayi during 1999, I was keen to repeat the process and the following is a description of this attempt from mating through to eggsac production.

12th April 2001
Male introduced and began vibrating body at the top of the females tube retreat. He entered the tube and the chamber at the base. The female struck out and he quickly retreated back to the surface. He moved to the far corner of her container and rested. During this period he 'chewed' on his palps for a few minutes as though readying them for mating. He moved down the tube again and the female reacted the same way but this time followed him up the tube until she was just below the entrance. The male shook his whole body at the tube entrance and she remained inside, forelegs raised in a defensive position. Again he moved to the corner to rest and 'chew' his palps while the female settled near the retreat entrance. After a few minutes he made his way back to her retreat and enticed her out by reaching into the tube and tapping her front legs. She responded and emerged completely from the burrow and he moved into position, front pair of legs supporting her under her chelicerae and second pair of legs continually flapping and stroking her front legs. Due to their fortunate position (female on a slightly higher piece of ground than the male) he had no trouble reaching underneath her. In the past the female has always seemed to hold her abdomen away from the male making it harder for him to reach, but this time this behaviour wasn't seen. He nervously reached underneath her and inserted his right palp for a split second then jerked backwards immediately as this is usually the time the female strikes. She remained passive, however, so the male quickly moved in again and inserted his left palp. Again he jerked backwards immediately and let go of the female although their legs were still touching. The female then gave the male a 'slap' with her front legs but not overly aggressively and they were then separated and he was removed unharmed. The females' epigynum was characteristically swollen afterward and she returned to her retreat.

Points to note:
1. The male was seen 'chewing' his palps once he knew the presence of a female was nearby. Again the male showed no real nerves towards the female and headed down the tube retreat without much hesitation. Even when the female reacted aggressively, he remained relatively calm. Was this 'chewing' of the palps a sign that he intended to mate and was readying his equipment?
2. Once the female realised it was a male invading her burrow she co-operated fully. This time she did not hold her abdomen away from the male but rather stayed in the normal position, allowing the male easy access to her epigastric furrow. The usual point of attack was passed uneventfully allowing the male to use both palps, something I have never seen when mating this species.

So why was the female so passive? Probably due to being happy in her environment. Having previously produced an egg sac showed that she felt comfortable with the set-up and since moulting just over three weeks previous, she was fed two large pieces of raw steak to try and sate her appetite. So ideal environment (temperature, humidity, availability of food etc) made the female 'happy' and therefore co-operative when mating. Taking these factors into consideration, hopefully she will feel comfortable enough to produce another egg sac. The male will be left for a few days and he will hopefully produce another sperm web to prove he is still viable then a second attempt will be made.

17th December 2001
The male was introduced again even though he hadn't made a fresh sperm web. This time the female was outside her burrow and the male was introduced to the opposite end to her. He began courtship than headed down the tube again and into the chamber, searching for the female. The female responded and moved to the entrance above. Eventually the male emerged behind the female and she initially responded aggressively. She willingly mated however but seemed to hold he abdomen slightly out of the way unlike last time. Cautiously the male reached forward with his palp and the female was seen to move her third pair of legs around the male (not a good sign for the male). The male inserted one palp and was killed immediately afterward. The female remained outside the burrow and consumed the male, abdomen first.

Points to note:
1. The male was eager to mate despite not building a fresh sperm web and the female remained relatively unaggressive when the male approached.
2. The act of the female closing her third pair of legs around the male proved she was going to strike on palp insertion. This is common with this species and many people believe their spiders have not mated, as the insertion is so rapid. Why would the female kill the male unless they have mated?

16th March 2002
Up to this point, the female was fed as much as she would take in an attempt to prepare her for eggsac production. Crickets were the staple diet (dropped into the artificial burrow) but I also fed several pieces of raw fat-free steak as additional nutrition. On cage inspection (16th March), the spider was seen constructing an eggsac but something was different to the previous one successfully produced in November 1999. Instead of the usual hammock-like web produced by most African species, suspended between the sides of the container, this eggsac resembled a normal mobile eggsac, similar to one produced by North American species. The eggsac was also produced in a very rushed manner (it can sometimes take several hours to a few days from initial silk spinning to actual laying). Photographs were taken during this period (see below) but the spider was disturbed as little as possible. After a few hours, the eggsac was complete and I left the spider to recover standing over the eggsac, hoping it would somehow suspend the eggsac during the night (this might have been the case as I hadn't seen the previous eggsac's construction).

The next morning I found the spider outside of it's burrow and the eggsac discarded in one corner. This was removed in an attempt to salvage the eggs for artificial incubation but when the eggsac was opened, the eggs were a light brown colour (as opposed to the usual yellow/cream colour) and had a faint bad smell to them. Within 24hrs the eggs had turned black and were very bad smelling (see below), obviously no spiderlings were going to emerge from these eggs. 48hrs later, mould have covered the eggs and they were discarded.
The female returned to her normal behaviour after this and moulted some five months later.

Points to note:
1. This eggsac was produced very quickly and without the usual care and attention given to fertile eggsac's, showing that the female knew there was a problem with the eggs.
2. Infertile eggs are quite often eaten to regain some of the valuable energy lost in eggsac production but these were discarded without being eaten. This again shows that the female was aware of a problem.

Conclusion.
So why did the female produce these bad eggs? Diet? Meat is often suggested as an additional food source for tarantulas during egg production but this case may suggest that it has a detrimental effect on the developing eggs. Eggs can sometimes turn bad and turn black but this usually happens over a period of weeks after being laid. It seems these eggs were laid already in a bad condition and it was only 24hrs before they were completely ruined. A previously successful eggsac was produced during 1999 but no meat was introduced into the females diet during incubation. Whether this has any bearing on the eggs final condition isn't known but I would recommend only feeding small amounts of meat, in quantities that the spider can consume within 12 hours (raw meat in the hot and humid environment of a tarantula cage can quickly turn rotten). I have also seen similar cases in T. blondi when they have been fed on a lot of defrosted pinkie mice.


At the time of writing (March 2004), the female is thriving and no meat is included in the diet this time so hopefully a fertile, healthy eggsac will be produced next time around.



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