Saguaros in the Night
(click on photos to enlarge)
Last week we drove over to Saguaro National Park West after sunset. We were hoping to watch bats visit the Saguaro Cactus blossoms which are abundant now. The buds open after dark and remain open until about midday the next day. They only last one day but since only a few open each day bloom time can last for weeks. We took one of those powerful flashlights along so we could see the flowers in the darkness.
Saguaro Cactus flowers (Carnegia gigantea)
We did see a few bats flying at dusk but none of the flowers that we watched had any visitors other than some insects which we couldn’t identify (probably moths). Despite the creepiness of getting out of the car in the dark (we had stopped for a Western Diamondback Rattlesnake in the middle of the road on our way in), we decided to venture a few yards along the Nature Trail. A Poorwill was calling in the distance. It was there that I spotted the tarantula — my first sighting of one since moving here. It was not especially large (about 2″) but I was happy to find it sitting just outside of its burrow and relieved that it posed for a quick photo despite the two million candle light beam illuminating it.
Desert Tarantula (Aphonopelma chalcodes)
When it decided it had enough of the light it retreated into its silk-lined burrow where it spends most of its time.
Desert Tarantulas are common to the Sonoran Desert. They can reach a body length of three inches which is not large compared to the Goliath Tarantula of South America which can have a body length of five inches and a leg span of twelve inches! I doubt I’d have been out in the dark looking for one of those.
Tarantulas don’t spin webs but catch their prey on the run. They do have one conspicuous enemy commonly seen flying around the desert during the day. It’s a robust wasp called the Tarantula Hawk (Pepsis sp.). It’s the female that pursues the tarantula which is the preferred host for her larvae. Locating the tarantula by smell, she will enter its burrow, evict it and sting it causing rapid paralysis. The tarantula is then dragged back into its own burrow where the wasp lays a single egg on the abdomen. She will then seal the burrow and the larva will feed off of the tarantula until it becomes an adult and exits the burrow. Fascinating!
Tarantula Hawks (Pepsis sp.) commonly nectar on milkweed.
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