JIM CONRAD'S
NATURALIST NEWSLETTER
Issued from Rancho Regenesis
in the woods near Ek Balam Ruins north of Valladolid in
Yucatán, MÉXICO

May 7, 2017

*****

A CUSTARDY CUSTARD-APPLE
Late one afternoon this week my Maya friend Gener brought me the pretty fruit shown at http://www.backyardnature.net/n/17/170507an.jpg

The fruit had just been plucked from a planted tree not far from the hut. With its size, shape, and black seeds embedded in pasty pulp, it was obviously a member of the Custard-Apple/Pawpaw Family, the Annonaceae, genus Annona, and in fact Gener's Spanish name for it was anona. Members of the genus Annona are much planted throughout the world's tropics, and often are see around folks' houses here, but in all these years I've never managed to eat one like this at the peak of its ripeness. Normally wild animals or other humans get to them before I do, or else they fall to the ground and rot before I see them. Also I was glad to have this fruit because it's taken me awhile to get the Annona concept, and this would help me get a fix on them.

My moldy old Bailey's Manual of Cultivated Plants mentions four Annona species planted in the world's tropics because of their edible fruits. Recently we looked at the spiky-fruiting Guanábana, or Soursop, Annona muricata, at http://www.backyardnature.net/yucatan/soursop.htm

Other times we've encountered the Cherimoya, Annona cherimola, often displaying small "finger-print depressions" over the fruit's surface, as shown on our Cherimoya page at http://www.backyardnature.net/chiapas/anona.htm

Another Annona species we've seen, variously called Saramuyo, Sugar-Apple, Sweetsop, and Anona, is Annona squamosa, and is shown with its fruits looking a little like an artichoke with succulent segments, at http://www.backyardnature.net/yucatan/sweetsop.htm

And then there's the Custard-Apple or Bullocks-Heart, Annona reticulata, which we profile at http://www.backyardnature.net/yucatan/anona.htm

So, is Gener's red fruit any of these, or something else?

It's the last one, the Custard-Apple, just with a red fruit instead of the pale one shown on our page. Gener tells me that around here three kinds of "Annona" are found: A red one, a green one and a yellow one.

In fact, one reason it's been hard for me to get these species straight was Gener's "three kinds of Annona" and the fact that the similar Cherimoya produces many cultivars that range in shape from nearly spherical to conical. One important feature that helped me separate the various Custard-Apple cultivars from the various Cherimoya cultivars is that Cherimoya tree leaves are invested below with dense, short hairs -- they're "velvety-pubescent." That's not so with our Custard-Apple.

And, to confirm that Gener's anona was a Custard-Apple, after savoring the fruit I visited the tree the fruit had come from. You can see several immature fruits still on the tree at http://www.backyardnature.net/n/17/170507ao.jpg

And you can see a leaf's hairless underside and its hairless petiole at http://www.backyardnature.net/n/17/170507ap.jpg

Therefore: Gener's red anona was a Custard-Apple, Annona reticulata, a red-skinned cultivar. And I'm here to tell you that when the flesh is perfectly ripe it's soft and sweet exactly like a deliciously rich custard dessert, only beset with sizable hard, black seeds you're obliged to spit out.

*****

"TOO MANY TOADS" UPDATE
Last week we looked at an orgy of Gulf Coast Toads in one of our ponds, and prophesied that too many tadpoles and then too many toads would result. This week on a visit to the same pond no toads were encountered but the pond's edges were busy with thousands of little black tadpoles, a tiny portion of which is shown at http://www.backyardnature.net/n/17/170507tp.jpg

So far the tadpoles don't seem to be suffering from overpopulation, except for the mid-day low oxygen content of their water, which they can deal with by clustering at the pond's edge and gulping air, as shown in the photo. Also, young tadpoles are vegetarian, and you can see that the pond's water and the white cement floor are greenish with algae, which the tadpoles eat.

However, as tadpoles grow, their bodies slowly metamorphose toward carnivorousness, so this story is not yet at its end.

*****

LOOKING INTO A NIGHT-BLOOMING CEREUS FLOWER
At http://www.backyardnature.net/mexnat/cereus1.htm we profile our local arboreal cactus known as the Night-blooming Cereus -- that common name being shared with several other species. As the above page shows, one spectacular feature of the cactus is its large, beautiful, perfumy flowers, which blossom for only one night. This week I paid special attention to a flower's pollination strategy. A view into the flower's throat is shown at http://www.backyardnature.net/n/17/170507cs.jpg

The numerous yellow items looking like tiny frankfurters dangling on slender filaments are the flower's male parts, the stamens. Notice how some hang from the corolla's "ceiling," while most mass on the "floor." A couple of tiny native bees gather pollen from the hanging ones. Are these small bees pollinating the flower? I don't believe they are the blossom's main pollination agent because the flower's greenish stigma extends beyond the stamens where probably the small bees seldom would land, and the stigma is the female part where pollinators are supposed to deposit their pollen. In he picture, the many-lobed stigma looks like an upside-down, greenish octopus emerging from beneath the stamen bunch on the floor. A better view of the stigma shown from the side is provided at http://www.backyardnature.net/n/17/170507ct.jpg

This looks like a classic bat-pollinated flower. Evidence supporting that idea include that the blossom opens at night, is the right size for a bat, and one can visualize how a bat might pollinate this flower. The approaching bat first touches the greenish stigma with its chest, which bears pollen from another flower, so from the first the flower gets pollinated. Then the bat scrambles over the bed of stamens and through the diffuse curtain of dangling stamens, getting doused with pollen grains to be carried elsewhere, and finally the bat receives its reward of nectar at the flower's back.

If this night-blooming blossom were pollinated by nocturnal moths, the corolla would narrow to a tube through which the moth's straw-like proboscis can be inserted, but a bat could never squeeze through.

*****

NECTAR ROBBERY OF PASSION FLOWERS
At http://www.backyardnature.net/yucatan/passion.htm we look at the horticultural Passion Fruit, also known as Granadilla and, locally, Maracuja. Nowadays a vine here at the ranch is loaded with blossoms, a close-up of the complex and beautiful center of one flower being shown at http://www.backyardnature.net/n/17/170507pg.jpg

Many of our vine's flowers are damaged. You can see one not yet expanded, but with one side completely ripped away, one of the pistil's three stigma arms broken off, several stamens missing and others mangled, and an entire sepal gone, at http://www.backyardnature.net/n/17/170507pf.jpg

This damage was caused by an animal robbing the flower's nectar, so who was the robber? My guess is that it was a bat, a rodent, or a bird and, if a bird, maybe an Altamira Oriole or Golden-fronted Woodpecker, both frequently seen here ravaging fruits such as oranges and bananas.

*****

DRY-SEASON FOREST UPDATE
Two weeks ago you saw what the nearly leafless, gray and wintry looking but stiflingly hot, late-dry-season forest next to the hut looked like. That picture is archived at http://www.backyardnature.net/n/17/170423dr.jpg

Last week we received two afternoon showers, one of 3mm (1/8th inch) and one of 4mm. That small amount seems to have been enough to cause many woody species in this area to issue small, undeveloped leaves -- enough for the woods to take on a slightly green but much-less severe aspect, as exhibited in a picture showing the very same trees and bushes this week, at http://www.backyardnature.net/n/17/170507d2.jpg

A close-up of a typical branch bearing immature leaves just emerging from their buds is at http://www.backyardnature.net/n/17/170507d3.jpg

If no new rains come, these emerging leaves well may dry up and die, similar to how leaves and flowers up north who emerge too early because of a warm spring, just to be killed by a late frost.

*****

SWALLOWS GATHERING
Last weekend I accompanied Ek Balam visitors to Río Lagartos on the Yucatan's northern coast. Along the beach east of Río Lagartos, throughout the afternoon Barn Swallows flew along the water's edge from west to east, on the average a bird passing about every ten or fifteen seconds. In past years I've noted that around this time of year Barn Swallow numbers along the northern coast may increase daily awhile, then one morning they're gone, presumably having judged that flying conditions over the Gulf of Mexico were good for their long flight northward, to the US's Gulf Coast.

So, this week I wondered what it might be like being a Barn Swallow. Would I be anxious about having to fly over such a big expanse of water? Would I be excited about soon experiencing the North's cooler weather and completely different vegetation? Or, would it all be instinctual, my thoughts and behavior being little more than mindless reactions to orders encoded in my genes?

Lately I've been in contact with a researcher studying Monarch Butterfly migration, and I'm told that first impressions based on genetic sequencing of Monarchs collected in the US and this area suggest this: That there's a fair possibility that our Yucatan Monarchs migrate via Cuba between Florida and here. Normally Monarchs migrating to Mexico are thought of as passing through Texas to overwinter in Mexico's central and southern highlands, with the Yucatan just not entering the picture.

Whatever the case, I suspect that migrating Monarchs with their much simpler brains are indeed almost like robots responding to commands encoded in their genes. However, I've seen enough of birds to know that individual birds can exhibit unique personalities, and that they have emotions. Therefore, it's not entirely silly to imagine a Barn Swallow sailing down the beach these days awe-truck by the ocean's frightful grandeur, and worried about having to launch out over it, with no visible landfall on the other side. The uncertainty of it all, so many feelings and nothing clearly understood...

And, how would it feel being one of those birds at the very moment the urge comes to stop flying along the beach, and head north? All the previous days' anxieties suddenly evaporated, the shore behind withdrawing into mists but nothing ahead except more and more ocean, but look at this: A vast diffusion of brothers and sisters all around making this same journey, taking the same gamble, all having felt just as I felt, and now feeling exactly as I'm feeling at last heading north, all of us now vanishing into... what?

*****

Best wishes to all Newsletter readers,

Jim

All previous Newsletters are archived at http://www.backyardnature.net/n/.