Sacs & slings

(For more information on the making and structure of eggsacs, check out the Eggsacs page as well!)

Wondering what to do if you have an eggsac? Don’t panic! Here are some basic guidelines on taking care of your eggsac and slings!

Widow eggsacs typically hatch anywhere between 25-40 days. Conditions play a huge role however, so these numbers are highly variable. With higher temps, eggsacs will hatch much faster than those kept at low temps. Humidity is also important in hatching a sac. Sacs in extremely low humidity will sometimes fail to hatch, and many of the slings will die before emergence. Variolus are fairly quick to come out of the sac, with mactans taking a little longer, and hesperus taking the longest.

If your female widow spider produces an eggsac, brace yourself for more. Female widows can produce several eggsacs per mating. With additional matings, even more are possible (check comparison of N.A. widow spiders for numbers!). If you caught your female outside, and she has not molted in your care, chances are a male has found her and done the deed before you picked her up. That excluding the highly unlikely scenario of intrusive opportunistic copulation. Also, N.A. widow females hardly ever produce ‘phantom sacs,’ unlike many of the other Latro species that do. So, odds are, your sac is fertile.

Eggsacs will contain anywhere from 1-500 slings. Typically females will produce more slings when very well fed and soon after mating. Sac numbers diminish as more and more sperm is used up. Some females can be re-mated, thus boosting up sac numbers and ensuring more sacs to be made.

There are many different approaches people take when a female drops a sac, and I’ve had success with all of them. Some of the different approaches include: leaving the sac with female for duration, leaving the sac with female and removing when it turns black, and removing the sac right away. Personally, I prefer to leave the sac with the creature who truly knows what it is doing and knows what’s best for the sac. I will, however, remove the sac when it starts turning very black (which will happen right before it hatches). The worst mistake you will make (and you will probably only make it once) is to leave the sac with the female, and to let it hatch in her cage. If you ever have any plans to separate slings, now you will not only have the headache of 300 slings exploding in opposite directions, but you will have an angry, venomous momma tired of being harassed. If you don’t plan on separating, only one spider will end up remaining as widows are not communal.

Containers that house eggsacs will vary and will serve different uses. A few I have used in the past with success include: large jar with a couple of sticks, and small empty deli with room for climbing. I will alter hatching chamber depending on my intent. I tend to avoid the upside-down setup for slings for ease of watering, feeding, and eventual separation. Bottom line: don’t stress over the container for hatchlings. Containers used should have some airflow, but not with big enough holes that the slings can get out. You could also keep them in an airtight container, cracking the lid for air, but I prefer the first option for many reasons which include: better overall airflow (seems to be pretty important for little guys), constant supply of air (which better mimics nature anyway), no ‘staleness’ in the cage caused by hanging or stifling humidity. I’ve had much better luck this way in rearing sacs.

Humidity is the singularly most important ingredient and factor in eggsac and spiderling care. There is no “magic number” when it comes to humidity percentage, but anywhere above ‘dry’ is a good start! Try your best to mimic the environmental conditions where the spider came from; so for example- if found in florida, give it high humidity, if found in Arizona, give it medium humidity. I learned the hard way with tropical species eggsacs being kept too dry. The slings will die and the eggsac will dry up.

Your intent (cannibalization or separation/selling) determines where you go from when the sac hatches. If you plan on keeping as many as possible (by the way, 300 mouths is A LOT to feed), then separate immediately after the first sign of cannibalization which will roughly be around the 2^nd or 3^rd instar. If you just want to keep a few healthy spiders, let them cannibalize down the number you plan on keeping. I usually let them cannibalize down to a number I can / want to handle. With rarer species, I usually separate very soon after the first few cannibalizations. With common species, only a couple survive. If you do plan on separating, small delis or other similarly sized containers will work. Small vials will work perfectly for many instars (maybe even up to 4^th or 5^th instar depending on size); I reared a geo to the antepenultimate stage in a very small vial. Maybe not ideal, but it will work perfectly.

Slings are especially sensitive to low humidity, so watering is a must with these little guys. Either mist the massive communal web, or provide a small cotton ball that will retain and release moisture. Droplets might be a slightly better choice. Feeding heavily will help as well.

When separating slings, I use a set of hypodermic needles (or something really really small). The smaller the better as there’s more maneuverability. I will usually crack the container, draw out a small piece of web from the inside with the needle (as there will be about 10 or so slings clinging on to the particular section). I also usually separate over a small plain white piece of paper and have several small vials handy to place over slings jetting for freedom. Many vials inevitably get used because they scatter in all different directions like pieces from a bomb.

It is not too difficult to care for and raise the babies. Do not, however, be discouraged when some die (think Darwin and survival). Their growth rate depends solely on you and the conditions you keep them in. They grow extremely fast when kept warm, humid, and sated. They grow slow when kept cold, dry, and lean. Growth rates can be found in the section of comparisons.

Feeding can be a couple different ways. I use a combination of both depending on circumstances. Both are effective. First, small prey can be dumped in the container (FFF, leafhoppers, etc) and slings will go crazy webbing up the small guys. They will even web and feed in groups. Some will even accidently web up their siblings! Another method is pre-killing crix (small preferable as large will rot much quicker) and placing directly in the web. The slings will find it and feed on it in large groups. Many crickets are better than just one so all your slings can eat.

Remember, the most important thing in spiderling care is water!