Bug o’the Week – Ants in My Plants Rerun

Bug o’the Week

Ants in My Plants Rerun

Salutations, BugFans,

Here we are, in the trough between Christmas and New Year’s. The interminable Christmas movies have been put to bed (YAY!), and reruns rule. Here, too.

Back in 2015, the BugLady suspended operations during the month of May, posting a teaser at the start of her month off – a fern fiddlehead with an ant crawling on it.  When she resumed her posts in June, she led with the story of that ant.  Here it is:

The results of taking off the month of May are in: many pictures of plants, flowering and non; not so many pictures of insects, even though the BugLady was checking plants like wild geranium, dandelions, and autumn olive that put out masses of flowers.  It’s a little worrisome.  The nannyberry is hopping, though – sweat bees, small twitchy wasps, syrphid/hover/flower flies, an occasional honeybee, etc.  And the first crop of dragonflies is emerging.  The other bit of fallout was that with no Tuesday deadline to aim for, the BugLady was, for the most part, clueless about which day of the week it was.  Adrift.

As promised, the story of the fern and the ant, a story that comes with a side order of botany.

It is hardly breaking news that plants produce nectar, a sugary liquid that the plant makes in nectaries that are located within the flowers.  Along with sugars, nectar may include amino acids, oils, vitamins, proteins, and more.  Why do they do it?  To attract the moths, bees, wasps, butterflies, and even hummingbirds and bats that inadvertently fertilize plants by carrying pollen to the next flower they visit.  “I feed you; you fertilize me.”  After fertilization, a plant may reabsorb its nectar.

BUT – a fair number of plants produce nectar in places other than their flowers, and these areas, called Extrafloral nectaries (EFN), don’t have anything (directly) to do with pollination.  EFN may be found on flower stalks, leaf axils, petioles, or leaf margins, or on various flower parts, and the nectar they provide is sweeter than the plant’s sap.  Some EFN are conspicuous; others are not http://edis.ifas.ufl.edu/in175.   Bracken ferns, which are non-flowering plants, have EFN at the bases of their three fronds as those fronds are just starting to unfurl.

Why do they do it?  EFN were originally (and erroneously) thought to be a waste disposal system for the plant, allowing it to get rid of metabolic by-products.  And while scientists are still not 100% sure why plants make EFN, they are probably there for ants and other predatory insects like ladybugs.

EFN could be decoys – “I feed you here, and you stay away from my flowers.”  It turns out that ants, despite their notable presence on flowers, are seldom effective pollinators.  Their exoskeletons are slick and are groomed frequently; they are pedestrians, which limits the number of flowers they can visit; and they don’t exhibit the “flower constancy” of bees, who will concentrate on a particular type of flower on a foraging trip, thus increasing the odds that the pollen they carry will be deposited on the correct species.  Plus, an antibiotic secreted by some ants and found on their exoskeletons kills pollen.  Ants do love nectar, though, and they may hog the nectar without delivering the payload and damage a flower in the process.

In the case of the bracken fern and its ants, it has always been assumed that EFN produce a reward for services rendered – an “I feed you; you protect me from herbivores” scenario – but here’s where it gets a bit sticky, scientifically.  Studies that measure the degree of protection contradict each other.  Researchers in the 1960’s described significant benefits to the fern foliage; recent studies suggest that while some grazers might be chased away in the early days as fronds are uncurling (when the plant produces the most sugar), there’s not a significant difference in foliage on ant vs ant-free ferns by the end of the season (when sugar secretion is very low).

Post-floral or pericarpial nectaries (PN) are much less common.  Some plants continue to produce nectar around the base of the flower after the petals fall and throughout the development of the fruits.  The foraging ants thus protect the seeds (or not, say some studies).  Apparently, garlic mustard has this in its bag of tricks.

Besides protection, ants provide other services to plants.  In exchange for food (and sometimes shelter – some plants have special structures where ants can live), foraging ants keep leaf surfaces clean, which helps keep plants fungus/disease-free.  Ants may prune or thin vegetation, optimizing growing conditions and reducing competition, and they may assist with seed dispersal.

Ant-plant interactions enjoy a lovely vocabulary.  A myrmecophile is an organism (usually an animal) that consorts with ants; myrmecophily (“ant-love”) refers to favorable relationships between ants and other organisms; and a myrmecophyte (“ant-plant”) is a plant that carries on mutually beneficial relationships with ants.  Through a process called myrmecochory (ant-dispersal”), ants spread and plant many wildflower seeds (according to some sources, ants “plant” almost one-third of spring ephemerals in eastern North America.  Bloodroot is one of them).  Attached to the seeds is an ant-attracting “packet” called an elaiosome.  After toting the seeds back to their nests, ants break off the elaiosome and eat it, leaving the seed to germinate.

There are close to 4,000 plants worldwide, in more than 100 plant families, in 745 genera, that grow EFN Thirty-nine are fern species.  Familiar practitioners include vetches (Vicia), gourds (Cucurbita), wild cherry (Prunus), elderberry (Sambucus), locust (Robinia), willow (Salix), wild sunflower (Helianthus), milkweed (Asclepias), and peony.  The BugLady found some on the petiole (leaf stem) of a high-bush cranberry.  When she first posted this, “The World List of Plants with EFN” was temporarily off-line.  It’s back http://www.extrafloralnectaries.org/.

Go outside – watch ants.

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’ the Week: The Twelve(ish) Bugs of Christmas

Bug o’ the Week

The Twelve(ish) Bugs of Christmas

Season’s Greetings, BugFans,

When the BugLady initiated this annual tradition in 2012 – showing pictures of bugs she had photographed but whom (objective case) she had already written about (OK – about whom she had already written) – she was already in trouble. Even that first year, she started with a Baker’s Dozen, not twelve, and each year she has managed to take herself firmly in hand and toss out a few dragonflies at the last minute in order to maintain that number (the Fourteen Bugs of Christmas almost happened this year).

At any rate, just hum along, add verses where necessary, and best wishes for smooth-sailing in 2022, with hopes for far fewer surprises than in 2021 (we’ve had enough character-building moments to last us for a while).

BALTIMORE BUTTERFLIES are exquisite butterflies with intricate lifestyles.  Eggs are laid en masse on their host plants (turtlehead, swamp lousewort, hairy beardtongue, and English plantain (a recent menu addition)), and newly-hatched caterpillars throw a web around the leaves https://bugguide.net/node/view/1614036/bgimage and feed en masse.  They overwinter in little clumps of partly-grown caterpillars inside rolled leaves on the ground, wake up in spring to a world devoid of turtlehead (a late summer plant), and switch their diets to the leaves of white ash (alas), arrowwood, wood betony, and a few others.  Later, they form a really spiffy chrysalis https://bugguide.net/node/view/117720/bgimage and then a dynamite butterfly.  Here in God’s country, they’re associated with wetlands, but in some parts of their range, they’re found in dry, open areas.

When the BugLady first wrote about the amazingly-colorful BLACK-LEGGED MEADOW KATYDID in 2013, she said that their faces are a little creepy.  She hasn’t changed her mind.  Find out more about them at https://uwm.edu/field-station/black-legged-meadow-katydid/.

DADDY LONGLEGS (sometimes called Harvestmen) ply the vegetation (and ground and walls and tree trunks) looking for small invertebrates to eat.  Although they are in the class Arachnida (along with spiders, scorpions, ticks, mites, and some others), they are in the daddy longlegs order Opiliones, rather than the true spider order Araneae.  They have eight legs and use six for walking; the other two are outfitted with lots of joints, so they’re extra-bendable, and with hair-like sensory receptors that they wave around as they go.  They don’t make silk, and they don’t make venom, but they do make stinky defensive chemicals, and if they’re alarmed, they may play possum.  They do not bite people – their mouthparts are simply too small.

This female EASTERN PONDHAWK DRAGONFLY, like other odonates, is an unapologetic carnivore, and her prey choices sometimes get close to home, taxonomically.  She is about to tuck into a male Eastern Forktail damselfly.

Some of our most common LIGHTNING BUGS/FIREFLIES are in the genus Photinus (there’s a good chance that this one is the Common Eastern firefly, Photinus pyralis).  Two cool things about Photinus: 1) their larvae https://bugguide.net/node/view/1653943 live underground, and “packs” of them may get together to hunt earthworms; and 2) each species of firefly has its own flashing code, to which the females (flightless in some species) respond with their own Morse code.  Game on.  But female fireflies from a different genus – Photuris – copy the Photinus signal, lure in an unsuspecting male Photinus, and then eat him.

Why?  Photinus fireflies pack a nasty-tasting defensive chemical (lucibufagin), which discourages predators like Phidippus jumping spiders, some songbirds, and possibly bats.  Photuris doesn’t produce defensive chemicals, but in eating him, she gets a good meal (the extra nutrition helps her make better eggs) and lucibufagin, too.  It makes her distasteful and, like a Photinus female, she passes it on to her eggs (it may protect them from ants).  https://news.cornell.edu/stories/1997/09/cornell-biologists-report-mimicry-and-murder-night

SWAMP SPREADWING DAMSELFLIES – Mating and ovipositing activity in dragonflies and damselflies often attracts a crowd – third party males hope to snag the female, dislodge the first male’s sperm, and replace it with their own.  That’s why the males of many Odonate species guard their brides, sometimes from the air or from a perch, but often by continuing to clasp the back of the female’s head.  Male number two (on the right) harassed this couple for a few minutes before moving on.

One chilly day in mid-October, the BugLady shared the bench on the hawk tower with this harmless, female PIGEON HORNTAIL/PIGEON TREMEX.  Pigeon horntails are primitive, non-stinging wasps that lay their eggs under the bark of dead/dying trees, and their larvae develop in/eat the wood.  She inoculates the wood with a white rot fungus when she oviposits, to soften the wood of the edible walls of her offspring’s chamber. That spine at the rear is her ovipositor (the horn for which she is named is the smaller point on top).  Alas – pressure-treated lumber – no joy – but together they counted 76 raptors that day!

The BugLady loves the “knock-your-socks-off” color combinations of mid-summer, often involving the radiant GREAT SPANGLED FRITILLARY.  This one is on Joe-Pye Weed.

Isn’t this DARK FISHING SPIDER a beauty!  And no shrinking violet.  A female’s leg-span may measure three to four inches, so they get people’s attention when they wander into the house (our DNR even issued an FYI in the form of a “warning” a few years ago when Dark Fishing spiders were especially numerous, which the BugLady suspects alarmed more people than it calmed).  Fishing spiders are in the nursery web spider family – they spin a sac for their eggs, use their mouthparts to carry it around until the eggs are close to hatching (and so cannot eat for that duration), and then attach it to a plant with (yes) a nursery web.  She stands guard over it until the spiderlings hatch and finally leave the case.  Dark fishing spiders are mostly found around water –  they walk on water, swim under water, leave scent trails across the water’s surface, and chow down on aquatic invertebrates and the occasional small fish or tadpole (https://uwm.edu/field-station/dark-fishing-spider/).

BLACK-AND-YELLOW MUD DAUBERS are solitary wasps that build and provision mud chambers for their eggs.  One source says that it takes thirty to forty trips to a mud source for her to construct just one cell, and she often packs multiple cells against each other in random blob https://bugguide.net/node/view/1480753/bgimage.  She may stash as many as 30 spiders into a cell before deciding that it’s ready for an egg – in behalf of her offspring she collects protein, but she herself feeds on nectar.  Solitary wasps are generally not aggressive, having neither hearth nor home to protect.  For more information, the BugLady is always happy to recommend the original Bug of the Week http://bugoftheweek.com/blog/2017/8/8/where-have-all-the-spiders-gone-black-and-yellow-mud-dauber-wasps-isceliphron-caementariumi-1.

The BugLady likes weevils – there’s something about the cut of their tiny jibs – and she always enjoys seeing this sparkly GREEN IMMIGRANT LEAF BEETLE (either Polydrus sericus/formosus or Polydrus impressifrons – they’re pretty similar).  These particular immigrants came over on the boat in the very early 1900’s.  Adult Green immigrant leaf beetles feed on leaves, and their larvae eat roots, but there are rarely enough of them around to be a problem.

SLUGFEST – The BugLady observed these slugs digging into a tasty fungus toward the end of summer.  Here are some (but not all) Fun Facts About Slugs gathered from a bunch of sources, sacred and profane: Slugs are hermaphrodites (housing both male and female reproductive organs), so any slug can lay eggs (self-fertilization is possible, but it generally takes two to tango); their body is called a foot; they are almost-shell-less gastropods (in the Phylum Mollusca, related to snails and limpets and more distantly to oysters, clams, cockles and mussels ((alive-alive-o)), octopi, and squid; one set of tentacles on the front of their head is light-sensitive and is tipped with eyes and the other is used to smell; like us, snails are mostly water, and their hygroscopic (water-attracting) mucous protects them from dehydration (among other services); slugs are not poisonous but they may carry parasites; they have a top speed of 0.3km/hour; snails have spiral bodies so they can fit into spiral shells – slugs don’t; the collective noun for slugs is “cornucopia;” slug blood is greenish; a slug has rasping mouthparts complete with approximately 27,000 teeth – more teeth than some sharks, and like sharks, slugs routinely lose and replace their teeth; a container half buried in the ground and half filled with yeast, water, and sugar (similar to beer) can lure slugs in and they will drown, but slugs prefer cheap beer over Oregon’s famed microbrews (compliments of the Oregon State University College of Agricultural Sciences “Slug Portal”); from Great Britain – it’s been estimated that an acre of farmland may support over 250,000 slugs, that the average UK garden has a population of over 20,000 slugs and snails, and that a cubic meter of garden can contain an average of up to 200 slugs; slugs can be active in temperatures as low as 41 degrees but snails can’t; slugs can stretch out to 20 times their resting length – all the better to squeeze through tiny openings; and lots of exotic species of slugs have hitchhiked to America (see previous fact).  And there’s so much more https://agsci.oregonstate.edu/slug-portal/education/q-questions-and-funnieshttps://www.uky.edu/Ag/CritterFiles/casefile/slugs/slugs.html, and https://carnegiemnh.org/leaping-slugs-did-that-slug-just-jump/ (and a video, of course).

And a TIGER SWALLOWTAIL in a pear tree.  This spectacular butterfly zipped in on the Black Chokeberry (which is in the same genus as pears) and was gone so fast that the BugLady only got one quick (and slightly out-of-focus) shot.

Ain’t Nature Grand!

Have a great holiday,

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

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