General question about spiders lifespan

[Otteresting]

Hello

I was wondering, what makes some spiders having a longer lifespan than others ? For exemple, why does Megatheloides females reach up to more than 10 years (according to some articles I've crossed), compared to some huntsman that lives for 3/4 years (also according to some caresheet I've read).

I'm not sure if these lifespans are correct, but I've read quite a few time that funnel-webs and trapdoors could live up to 20 years in some cases.

What in the name of biology make these spiders living longer than others ?

Thanks you to enlighten me on the subject !

 

[chanda]

This is just armchair theorizing here, but I'd guess that activity level and metabolism play a large part. Compare the lifestyle of a huntsman spider - a speedy hunter that chases down its prey - with that of a trapdoor spider - a patient ambush specialist that waits for food to come to it. Because it is more active, the huntsman uses more energy, therefore it has to have more food, therefore it has to expend energy more often to catch that food. It will need to have a relatively fast metabolism (for a spider). The trapdoor spider, on the other hand, rarely moves - except for those rare (and incredibly short) bursts of speed every few weeks or so, when it is hungry and prey is just outside the door. Another indication of the huntsman's faster metabolism is its growth rate. It will grow faster and molt more frequently than the trapdoor spider.

It would appear that the faster growth rate and metabolism are related to a shorter lifespan.

Even within a given species, you can see the effects of faster growth on lifespan. For example, anecdotal evidence from people who "power feed" tarantulas and keep them at warmer temperatures suggests that they can get them to grow and mature faster than those that are kept slightly cooler and fed less often, but - at least for males, who typically stop molting after maturity and have only a limited life remaining - the earlier maturity leads to an earlier death. (With female tarantulas, who continue to molt and grow for years (or even decades) past maturity, any shortened life span due to accelerated growth early in life would be negligible.)

You can also see the effects of activity level on lifespan when you compare the lives of insects like silk moths that do not eat as adults, relying solely on energy reserves they stored up as caterpillars. Males are more active, flying around in search of females - and they die sooner, having expended that energy. Females are less active, frequently sitting still and waiting for the males to come to them - so they live slightly longer, pumping out eggs for the next generation.

 

[Otteresting]

This is just armchair theorizing here, but I'd guess that activity level and metabolism play a large part. Compare the lifestyle of a huntsman spider - a speedy hunter that chases down its prey - with that of a trapdoor spider - a patient ambush specialist that waits for food to come to it. Because it is more active, the huntsman uses more energy, therefore it has to have more food, therefore it has to expend energy more often to catch that food. It will need to have a relatively fast metabolism (for a spider). The trapdoor spider, on the other hand, rarely moves - except for those rare (and incredibly short) bursts of speed every few weeks or so, when it is hungry and prey is just outside the door. Another indication of the huntsman's faster metabolism is its growth rate. It will grow faster and molt more frequently than the trapdoor spider.

It would appear that the faster growth rate and metabolism are related to a shorter lifespan.

Even within a given species, you can see the effects of faster growth on lifespan. For example, anecdotal evidence from people who "power feed" tarantulas and keep them at warmer temperatures suggests that they can get them to grow and mature faster than those that are kept slightly cooler and fed less often, but - at least for males, who typically stop molting after maturity and have only a limited life remaining - the earlier maturity leads to an earlier death. (With female tarantulas, who continue to molt and grow for years (or even decades) past maturity, any shortened life span due to accelerated growth early in life would be negligible.)

You can also see the effects of activity level on lifespan when you compare the lives of insects like silk moths that do not eat as adults, relying solely on energy reserves they stored up as caterpillars. Males are more active, flying around in search of females - and they die sooner, having expended that energy. Females are less active, frequently sitting still and waiting for the males to come to them - so they live slightly longer, pumping out eggs for the next generation.

That's what I was thinking, but that's relatively strange there are many species of house spiders that doesn't really live for long even tho they are quite static. I bet that's just a matter of metabolism speed, or how evolution favorised their lifecycle. In captivity, some spiders won't move much than that, but still, they won't necessarily live much longer than in wild conditions. Thanks you for your answer !

 

[Ungoliant]

One thing the longest-lived spiders (mostly mygalomorphs) have in common is that the females continue to molt as adults. However, I don't know if that is the cause of their longevity or merely a symptom.

 

[Otteresting]

One thing the longest-lived spiders (mostly mygalomorphs) have in common is that the females continue to molt as adults. However, I don't know if that is the cause of their longevity or merely a symptom.

I don't really have much of experience with araenomorphae(s), but does females keep molting even when they gets adult or or will they stop just as males does ? (Supposing that females does have more molts in their "lifecycle"). I've read that Nephila spiders would stop molting as mating season arrives, and this for their remaining lifespan.

I guess long lifespan is just one of the caracteristics that defines funnel-web and trapdoor spiders. I've been pretty suprised when I learned they could live as long as tarantulas, which led me to post here.

Btw I just read that Dipluridae are classified as mygalomorphs, which I didn't know when I posted. It kinda explain why Linothele does have such a great lifespan. I've been mistaken thinking they were araenomorphs

 

[Ungoliant]

I don't really have much of experience with araenomorphae(s), but does females keep molting even when they gets adult or or will they stop just as males does ?

Most araneomorphs stop molting upon sexual maturity. However, there are some exceptions, mainly among the more primitive haplogynes.

 

[Otteresting]

Most araneomorphs stop molting upon sexual maturity. However, there are some exceptions, mainly among the more primitive haplogynes.

Thanks for the info! Thought molting until death was a common fact for all female spiders

 

[SonsofArachne]

This is just armchair theorizing here, but I'd guess that activity level and metabolism play a large part

Sicarius support your theory. A "true spider" that has a long life span - up to 15 years, I've read - they don't do much but sit under the sand and wait for prey.

That's what I was thinking, but that's relatively strange there are many species of house spiders that doesn't really live for long even tho they are quite static.

While they do mostly sit in their webs, their webs have to be replaced frequently, which would require both physical effort and bodily resources to produce all that silk.