Pollinator Post 8/27/26
Back to my beloved Oregon Gumweed, Grindelia stricta on the shoreline of Bay Farm. The white foamy masses of Spittlebugs seem to be increasing in number every day.
A Sedgesitter, Platycheirus sp. (family Syrphidae) is resting on a Grindelia leaf, seeming to be enjoying the morning sun.
The Sedgesitter, Platycheirus sp. (family Syrphidae) is found in grass and herb vegetation. Adults of many species feed on pollen of wind-pollinated plants, such as Salix, Plantago, Poaceae, Cyperaceae, but they also visit other flowers. Many stay active during cold and rainy weather. Larvae feed on aphids.
Hey, that’s a Grindelia Weevil on that flowerhead!
The “Grindelia Weevil” typically refers to snout beetles (family Curculionidae) that utilize gum weeds (Grindelia species) as their primary host plants. The most notable association belongs to the genus Anthonomus. Anthonomus squamosus and Anthonomus ater rely specifically on Grindelia (family Asteraceae) for larval development. These are small beetles featuring the classic weevil snout, often marked by distinct beige, white, or pale longitudinal stripes on their elytra. Adults feed on flower petals and anthers. Females deposit eggs directly into the plant tissues. The small, white, legless larvae feed internally on the seed heads, flower buds, or stems until they pupate and emerge as adults.
An unfamiliar insect with a bulbous abdomen scurries away as I approach for a better look.
I offer it a finger and it climbs on. Ah, it is a true bug (order Hemiptera).
In “true bugs” in the suborder Heteroptera, the unique front wings are called hemelytra; these are divided into a leathery base and a membranous tip. The hind wings are completely thin, delicate, and membranous, hidden underneath the front wings when at rest. When the wings are not in use, they lie flat across the insect’s back, often overlapping to form a distinctive “X” or diamond shape.
See that needle-like mouthpart (rostrum) that is folded under the body of the bug? That is the distinguishing characteristic of the “true bugs” or Hemiptera.
The elongated, needle-like beak used to pierce and suck plant tissue or prey, the rostrum is folded beneath the body when not in use.
The bug is missing its left hind leg.
Wow, the bug is literally dragging its huge abdomen around. A gravid female? Despite my best efforts taking these pictures, iNaturalist is not able to offer an identification of the bug.
A Cellophane Bee, Colletes sp. (family Colletidae) is foraging on a Grindelia flowerhead. The small bee has black-and-white striped abdomen and its body is fuzzy all over.
The bee family Colletidae includes generalists and specialists, and they are likely important pollinators of many wildflowers. All Colletidae in North America are solitary ground nesters, but some species nest in large aggregations. There are two major genera of Colletidae in North America: the Masked Bees (genus Hylaeus) and Cellophane Bees (genus Colletes). The most obvious shared characteristics of Colletidae is also the hardest to see: their short tongue. Colletes are moderately hairy, slender bees, ranging in size from 7 to 16 mm. Distinct features include a hairy head and thorax, pale bands of hair on the abdomen, and a heart-shaped head. The eyes of Colletes are angled (rather than being parallel), making the face slightly heart-shaped. The eyes of Colletes are angled (rather than being parallel), making the face slightly heart-shaped.
The genus name Colletes means “one who glues”, referring to their habit of applying a glue- or cellophane-like lining to the walls of nest cells, using their specialized tongues. This lining gives rise to their common names: cellophane bees, polyester bees, and plasterer bees. Colletes tongue is unique: short, flat, and forked at the tip. Colletes line their nests with a distinctive cellophane-like substance made from saliva and secretions from the Dufour’s gland on the abdomen. Using their specialized tongue, they paint the walls with saliva, then with secretions from the Dufour’s gland, they add a coat of varnish. This creates a clear covering that is strong, durable, and resistant to mold and water.
A male Western Leafcutter Bee, Megachile perihirta (family Megachilidae) is repeatedly flying to the base of a grass stem, and running up swiftly to the tip to launch himself into the air. I have often seen this odd behavior in the past, but am thrilled to be able to capture it on camera today.
The male is apparently performing a mating strategy and territorial behavior. Male Western Leafcutter Bees exhibit this repetitive running and launching routine due to a combination of distinct biological drives.
(1) Scouting for females (Patrolling)
Male leafcutter bees do not help build nests or collect pollen for the young. Their primary goal in adulthood is to find a mate. By running to the highest point of a grass sten and launching into the air, the male maximizes his field of vision. He scans the immediate area for foraging females visiting nearby flowers. If he spots a female, he will attempt to dive-bomb or intercept her mid-air to initiate a mating attempt.
(2) Defending Territory
Male leafcutter bees are highly territorial over prime locations, such as patches of flowers or active nesting sites. A tall blade of grass serves as a perfect lookout tower. The male will aggressively chase away competing males or other insects that enter his designated airspace to ensure he has exclusive access to any females that arrive.
(3) Pheromone Dissemination
Many male leafcutter bees feature unique physical adaptations, such as expanded, pale, or hairy front legs that contain specialized scent glands. As they run up the stem and rapidly take flight, the physical exertion and wing motion help release and broadcast these pheromones into the wind. These chemical signals advertise his presence to nearby females and warn competing males to stay away.
A Broad-nosed Weevil, Pantomorus sp. (family Curculionidae, subfamily Entiminae) is hidden among the terminal leaves of a Grindelia. Note that when resting, the basal section of its elbowed antenna is held in a groove along its snout, while the distal section hangs free.
Pantomorus is a genus of flightless, broad-nosed weevils in the family Curculionidae. They are grayish-brown beetles about 7 to 9 mm long with a short, broad snout and a faint pale mark on either side of their wing covers. Adults chew ragged, serrated notches along the margins of leaves on roses, citrus, and various ornamentals. All adults are female and reproduce asexually. The larvae are legless, thick-set, yellowish grubs that drop to the ground after hatching and feed on plant roots for several months; this can stunt plant growth or invite fungal infections. One generation occurs per year, with adults emerging mainly from mid-summer through autumn, though some appear year-round.
I spend some time looking for adult Spittlebugs near the foam masses that the nymphs have created.
Spittlebugs, also known as Froghoppers belong to the superfamily Cercopoidea within the order Hemiptera (true bugs). While sometimes generally referred to as the family Cercopidae, they are scientifically divided into several families, primarily Aphrophoridae (common spittlebugs), Cercopidae (froghopper), and Clastopteridae.
Why the common name of “spittlebug”? The nymphs (immatures) of these bugs create foam masses on plants in which they live and feed. Like the adults, the nymphs use their piercing, sucking mouthparts to feed on plant juices. The nymph produces a cover of foamed-up plant sap reminiscent of saliva, hence the common name of spittlebug. Whereas most insects that feed on sap feed on the nutrient-rich fluid from the phloem, Spittlebugs tap into the much more dilute sap flowing upward via the xylem. The large amount of excess water that must be excreted and the evolution of special breathing tubes allow the young spittlebug nymphs to grow in the relatively protective environment of the spittle. Symbiotic bacteria in the insects’ digestive system provides them with the essential amino acids that their diet lacks. The foam serves a number of purposes. It hides the nymph from the view of predators and parasites, and it insulates against heat and cold, and protects the delicate nymphs from desiccation. Moreover, the foam has an acrid taste that deters predators.
Unlike their young, adult spittlebugs (also known as Froghoppers) are efficient flyers and hoppers, feeding on diverse plant species. They pierce plant stems to feed on xylem. To get enough nutrients, they consume massive quantities of sap, drinking up to 280 times their body weight daily, resulting in high waste excretion. Froghoppers can cause damage by distorting plant leaves and causing shoot tips to die back.
An adult male Spittlebug, Complex Clastoptera lineatocollis (family Clastopteridae) is resting on a Grindelia leaf above a foam mass. It is predominantly black with dull, reddish purple eyes and striped legs.
I tilt the Grindelia stalk to get the Spittlebug into the light. The short hairs on its wings light up as white specks. I find only males today. Maybe the brown females are harder to spot on the plants?
The Spittlebug, Complex Clastoptera lineatocollis (family Clastopteridae) is found in western United States. The bugs feed mostly on Asteraceae, although other hosts have been reported. Females are brownish (3.3-3.8 mm), while the smaller males (3.0-3.2 mm) are mostly black.
The adult Spittle Bug is sometimes called a Froghopper. The Froghopper is a “true bug” in the order Hemiptera. Froghoppers are champion jumpers among insects, out-performing even the fleas. The bug can leap the human equivalent of a skyscraper without a running start. It is the highest jumping insect proportional to body size. The muscles in its hind legs act like a “catapult” to release energy explosively.
Athletic prowess aside, the Froghopper is better known for its young, the “spittle bug”. The nymphs produce foamy white masses on plants within which they feed on plant sap. Froghoppers have piercing-sucking mouthparts, and feed on plant sap as both nymphs and adults. A recent report claims, “Froghoppers are the super-suckers of the animal world. The tiny insects produce negative pressures equivalent to people sucking a 100-meter-long straw.” The sucking power is strong enough to suck the water out of a cup at the base of the Statue of Liberty while perched on its crown. To complement that, the Froghopper is also exceptional at urination, excreting the human equivalent of 2,500 gallons of urine a day.
As I pause to admire the developing acorns on a Holm Oak, Quercus ilex, my eyes are naturally drawn to the terminal leaves that have been silked together. Some debris has been cast out of the silken fortress. It has every appearance of a Yellow Sac Spider shelter that has been used for a nursery.
Cheiracanthium spiders, commonly known as Yellow Sac Spiders, are wandering nighttime hunters that do not build traditional prey-catching webs. Instead, they construct distinct, silk “sac” retreats during the day to rest, molt, mate, and guard their eggs. In gardens and on foliage, these spiders frequently draw terminal leaves together, silking the edges to form a protective tube, “tent”, or folded retreat. These retreats are built almost daily, often completed in a single night. The silken sacs provide camouflage and protection from predators, and they also serve as a crucial, protected nursery where the female will lay and guard her eggs.
Zooming in on the debris, I find hatched spider eggs as well as spiderling exuviae. After her spiderlings have molted and left their home, their mama has cleaned house so she could reuse the space.
Other retreats on the oak are less sturdy, but all come with obvious openings.
This one is even more wispy.
A small wasp with very long antennae is investigating a flower of Hooker’s Evening Primrose Oenothera elata. The ovipositor at the tip of its abdomen tells me it is a female parasitoid wasp, probably in the family Ichneumonidae.
The Ichneumonidae, also known as the Ichneumon Wasps, or Ichneumonids, are a family of parasitoid wasps. They are one of the most diverse groups within the Hymenoptera (the order that includes the ants, wasps and bees) with about 25,000 species and counting. Ichneumon Wasps attack the immature stages of insects and spiders, eventually killing their hosts. They play an important role in the ecosystem as regulators of insect populations.
The Ichneumon Wasps have longer antennae than typical wasps, with 16 segments or more as opposed to 13 or fewer. Ichneumonid females have an unmodified ovipositor for laying eggs. They generally inject eggs either directly into their host’s body or onto its surface, and the process may require penetration of wood. After hatching, the Ichneumonid larva consumes its still living host. The most common hosts are larvae or pupae of Lepidoptera (butterflies and moths), Coleoptera (beetles) and Hymenoptera. Adult Ichneumonids feed on plant sap and nectar. Females spend much of their active time searching for hosts while the males are constantly on the look out for females. Many Ichneumonids are associated with specific prey, and Ichneumonids are considered effective biological controls of some pest species.
I am startled to see a striking Stink Bug with bold red-and-black patterns perched on the flower buds of a Wild Radish. As I look around, I find about a dozen of the insects on the same plant. iNaturalist has helped identify it as a Harlequin Bug, Murgantia histrionica (family Pentatomidae).
The Harlequin Stink Bug, Murgantia histrionica is a brightly colored shield-shaped insect native to the Americas that feed heavily on crops in the mustard family, Brassicaceae. Adults are about 3/8 inch long with a flat, shield-shaped body. They are glossy black with striking red, orange or yellow markings. They use piercing-sucking mouthparts to drink sap and juices from plant tissues. Preferred plants are cruciferous crops like cabbage, kale, collards, broccoli, cauliflower, radishes, and turnips. The feeding causes leaves to develop white, yellow, or cloudy spots (stippling). Heavy infestations cause wilting, brown dead patches, stunted growth, or plant death. Eggs are distinctive white barrel shapes with black bands, laid in neat clusters of about 12 on the undersides of leaves. Like other stink bugs, they release a foul smell when disturbed or threatened.
A pair of Harlequin Bugs is mating on the underside of a Wild Radish leaf.
Stink Buts mate rear-to-rear in a process that can last from several hours to multiple days. They find each other using scent signals called pheromones and low-frequency vibrations or sounds, and the female often drags the male around or continues eating while connected. After mating, females lay clusters of 20 to 30 tiny, barrel-shaped eggs on the undersides of plant leaves. A single female can lay hundreds of eggs over her lifetime leading to multiple generations a year in warm weather.
An Oblique Streaktail, Allograpta obliqua (family Syrphidae) is feeding on pollen of a Wild Radish flower.
Although small in size (6-7 mm long), the Oblique Streaktail is easily recognizable for the unique pattern on its black-and-yellow abdomen. It is a common North American species of hover fly. Adults visit flowers for nectar and pollen, and are pollinators. Females lay eggs on plant surfaces near aphids. Larvae feed on the aphids.
Hey, that’s a hover fly pupa lodged between the flowers of Fennel, Foeniculum vulgare.
Hover fly pupae are the teardrop-shaped, transitional life stage where mature larvae metamorphose into adults. They often start out greenish and translucent before shifting to tan-brown or taking on the colors of the developing adult inside. Depending on the species, pupation happens directly on the host plant’s foliage near where the larvae fed on aphids, or down below in the loose soil, mulch, and leaf litter. Pupae need damp conditions or high humidity to successfully mature. If it is too dry, mature larvae crawl down into the soil to find moisture. The pupal stage typically lasts about one to two weeks before the adult hover fly emerges. Many species survive the cold winter months by remaining as pupae hidden in protected leaf litter or topsoil.
A female Oblique Streaktail, Allograpta obliqua (family Syrphidae) is foraging on the flowers of Fennel. I am seeing a lot of these hover flies lately.
What are those white structures on the side of the hover fly’s thorax? In the past, an entomologist friend has suggested that they might be phoretic mites that hitchhike on insects. But these have such irregular shapes and sizes, I am beginning to have doubts. Looking through hundreds of photos on iNaturalist, I actually found one that has almost identical structures on an Oblique Streaktail in Minnesota! Well, that sure clinches the case that these are not mites, but are intrinsic parts of the fly’s anatomy. Could they have a functional role in flight? Why white?