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Megasoma punctulatus question


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Now is the time to get them. I have not bred them in awhile because I pretty much stopped breeding, too much work making flake soil. But they are pretty easy to breed and not too hard to find. The best spots are in the Rio Rico area of Arizona. They are probably out now. They are on the mesquite trees at night and also come to black lights.

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Last night, 16 August 2022, about 70 miles north of "traditional" locations for M. punctulatus in Arizona, associated with a different riparian system. Four females at light. This population is always late, with adults being usually observed around the last week of August and first week of September. Since I located the beetles, now about 10 years ago, I have searched and searched and searched mesquite trunks and then other species of trees for lekking groups with males, but never seen them anywhere other than at light. I've never seen a wild, living male at this location. So, without associated males, dissection or some molecular work...I will call these Megasoma cf punctulatus for now 

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Thank you for your report. No males, that is really strange. Generally you will get 70 males on the Mesquites and then about 8 females at the lights. Sometimes I find the females on the trees but most of the time it's mating with a male. I had a friend go to the traditional location two weeks ago and got about 70 plus males on trees and about 10 females at his lights. What is CF?

I have not gone to AZ this year but from reports, it's been a great year for collecting. I guess the monsoons hit super hard. I saw more reports than normal of collectors getting Mp at various places that were not at the traditional locations. Like Madera Canyon, Pena Blanca, etc. Maybe it will be a great year for D grantii as well.

Just FYI, I have a friend who would find larvae at the base of trees a few inches underground. He would look for holes and dig down. I personally never found any that way. 

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In 2019, around 1 September, I found eleven females at these same lights in the same location on one night. I got out my headlamp and searched nearby mesquite, acacia, hackberry, and Sapindus trunks for males for at least two hours...and found absolutely nothing.

I'm looking higher now in the twigs, branches and upper trunks of the trees.

Garin, do you have any information about timing during the night when you or your buddies find Megasoma on trunks? Is it 9 PM? Before midnight? Do beetles disappear later in the evening? Is there a time during the night that is best?

It's a mystery inside an enigma

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Generally we see the males right away. Right as the sun goes down. I have seen them flying around at dusk. It does seem to drop off after the first 2 hours of darkness but you can still find a few here and there at midnight. But the peak seems to be that first 2 hours. As the season goes on, we will often see more females at lights and less males on the trees. So like most species, the females seem to last longer in the season and males start to disappear. It's very interesting that you don't see males. 

I'm sure you have done this but have have gone out in the area very early in the season? Or possibly very late? Just curious if by chance, the males come out very early and disappear fast. However, that seems unlikely. The year that I have seen the highest ratio of females to males is a year that we came sort of late. Generally there is lots of males on the trunks, often 3 on one trunk. That year, there was very few males out but we got lots of females at black lights. I had assumed it was because we were late but not sure. It was the most females I had ever seen, about 15, and it was a very small amount of males, about 20 or so.

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Some of the other "desert" Megasoma species (thersites, pachecoi, sleeperi, "lenczyi") can be found during the daytime "gumming" twigs of their hosts, sometimes in sizeable congregations (see thersites observations on iNaturalist). But I don't know if I could search during the day at this location without getting the attention of the authorities, since it's all, technically, private property...

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The only other Megasoma I have collected is M sleeperi. I was told when I first started looking about 10 years ago to look on the PV trees at dawn. You can also try at night, etc. I looked and looked and looked and found nothing. I later met a former biologist that had been collecting over 35 years and this guy was a life changer for me. Told me how to find so many things that I had trouble finding. He had an extensive collection of M sleeperi as well as most Arizona species like M punctulatus, etc. I told him about looking for M sleeperi on PV trees and he said he called that the walk of a 1000 trees. He said, yes, he has found them that way before but that is the most inefficient way to find them. He said you could easily look at 1000 trees and find none. He told me of a different spot and how to set up my lights and I caught 6 on the first night. But of course, every species and location is different so it's hard to say. So not sure it's worth looking in the daytime. Especially if you could get in trouble. Just seems like too much effort, haha. It's like looking for D grantii on the trees in the daytime. Yes, you can find them that way. But why not setup an MV in a good spot and get 50 while sitting in a lawn chair.

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Perhaps that is what is happening-- I am out looking generally later in the evening. I mean generally after 11 PM. 

I have been out at this site in July looking. But generally I've skipped the early part of August.  It is possible I've missed males by looking too late in the season, as I generally stick to "granti time."

This is the earliest I've seen Megasoma at this site. But some areas of southern Arizona have had rain since 9 June, with major, widespread storms as early as 18 June ("traditional" start of our monsoon rains should be around 4 July). So, all seems early this year.

A granti on 4 August 2022 in the Santa Rita mountains. That's nearly a month early

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Nice D grantii! Yes, I have heard reports of D grantii being out very early in various parts of Arizona. I was at Harshaw one year, I think around August 10th and I was very surprised to get about 10 D grantii that came to my MV light. I had been there about 4 times before and never got one. I've gone a few times since then and I have not seen one.

Yes, 11 pm sounds very late. I would definitely try right at darkness. But it still seems that you would find at least one. For me, they are much more difficult to find that late in the evening. 

 

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UPDATE: night of 21 August 2022. I got to the site at about 10 PM, immediately looked for female Megasoma around the lights at the side of the building where I usually find them-- nothing. Then, because the lights only shine out over the property to the west, I put on my headlamp, crossed the four-string barbed wire fence and began searching every bole of every tree on this property. On about the 18th tree (close to the fence of the parking lot where the lights are located), I finally found a male on a mesquite trunk about six feet from the ground. One. I searched trees for about an hour more, as close to the dwellings as I dared. Only the one male...and no females showed at the lights last night. I left after midnight...

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