Katydids, also known as bush crickets or long-horned grasshoppers, are a group of insects found worldwide. There are over 6,400 species of katydids, characterized by their long antennae and the males’ loud mating calls. While katydids may resemble grasshoppers, they actually belong to a different insect order called Orthoptera. One question that often comes up about katydids is whether or not they can fly.
Can katydids fly?
The simple answer is yes, katydids are capable of flight. However, their ability to fly varies by species. Some katydids are stronger fliers than others based on the size and structure of their wings.
Katydids have two pairs of wings: forewings and hindwings. The forewings are narrow and leathery, while the hindwings are broad and more membranous. When katydids are at rest, their wings are folded tent-like over their body with the hindwings underneath the forewings. This helps camouflage them in vegetation.
To take flight, katydids spread their wings and flap the hindwings to generate lift. The forewings don’t contribute much to flight; instead, they help stabilize and steer the insect. The wing-folding structure allows katydids to pack away their hindwings neatly beneath the forewings when not in use.
Species with broader, more expansive hindwings like field katydids and greater anglewings are typically better fliers. They can sustain flight for distances up to a few hundred feet. In contrast, bush katydids and shieldback katydids with smaller wings may only be able to glide or flutter short distances.
When do katydids fly?
Katydids are most active at night and mainly fly under cover of darkness. During the day, they typically remain very still among foliage to stay hidden from predators. After nightfall, the males take flight to find mates.
Night provides katydids protection from birds and other daytime predators. Their green or brown coloration also helps camouflage them on vegetation during daylight hours when they are most vulnerable. Taking flight at night makes it safer for katydids to disperse, forage, and seek mates.
Cooler, humid conditions are ideal for katydid flight. On warm, dry nights, they tend to stay put instead of expending energy in flight. Rainy or windy weather may also deter katydids from flying.
In the late summer and fall, mature katydids take wing in search of mates. This coincides with the peak mating period before winter dormancy. The males’ loud courtship calls serve to attract flying females at night.
Why do katydids fly?
Katydids fly for several important reasons related to survival and reproduction:
- Dispersal – Flying allows katydids to colonize new habitats and expand their range.
- Foraging – Some katydids take flight to reach new food sources like leaves, fruits, and flowers.
- Mate-seeking – Flying at night helps male katydids locate receptive females by their pheromone plumes.
- Predator evasion – Taking flight helps katydids quickly escape predators on the ground.
Dispersal, in particular, allows katydids to avoid inbreeding and overcrowding by spreading out. Long-distance flying species can colonize habitats miles away. Even shorter flights help expand the gene pool as katydids breed with members of distant populations.
Strong flight capability is also beneficial for foraging. Some katydids prefer specific host plants, so being able to fly between isolated food sources is advantageous.
When it comes to mating, flight provides male katydids access to more potential mates. Females give off pheromones to attract males from afar. Flying allows males to pick up these scents and pinpoint the female’s location. In species where females are also good fliers, aerial mating may occur.
Lastly, flight offers an effective escape from predators like birds, mammals, and other insects. Katydids frequently take flight when threatened to get themselves out of harm’s way quickly.
How far do katydids fly?
Most katydids engage in routine, short flights close to the ground. They may flutter between blades of grass or across small clearings. This allows them to forage and disperse locally without overexposing themselves.
However, some katydid species are capable of long-distance migrations high in the air. For example, the flight range of the oblong-winged katydid spans up to 5 km (3 miles) in a single night. The great green bush cricket has been recorded dispersing up to 7 km (4.3 miles) downwind.
Field studies show katydid migrations tend to follow linear habitats like tree lines, rivers, and highways. These landscape features provide landmarks, shelter, and food during stopovers. Wind patterns also influence the direction of migratory flights.
One study tracked the movement of the flight-capable bog bush cricket over several generations. Over the course of a breeding season, the average distance covered was 2.2 km for females and 1.8 km for males. But a small number dispersed more than 7 km away from their starting points.
In general, katydids with broad hindwings and large wing surface areas have greater long-distance flight capability. Larger species like bush crickets can travel farther than smaller katydids like meadow katydids.
Flight adaptations
Katydids possess several key adaptations that enable flight:
- Wings – Hindwings are thin and expansive to generate lift, while forewings stabilize the flight path.
- Powerful flight muscles – Flight muscles make up a large portion of the thorax.
- Lightweight exoskeleton – The lightweight exoskeleton reduces body weight to make flight easier.
- Energy stores – Katydids build up fat reserves to fuel migratory flights.
- Keen senses – Large eyes and antennae help navigate and avoid obstacles in flight.
In some migratory species like the oblong-winged katydid, the wings have evolved to be up to one-third larger in migrating populations. This suggests strong selective pressure for enhanced flight performance.
Katydids also conserve energy in the days prior to a long flight by reducing activity and feeding. Special fat body tissues store up lipids that can power sustained flight for several hours or longer through metabolic oxidation.
Rapid twitch muscle fibers in the wings allow katydids to beat their wings up to 30 times per second on takeoff. Once in cruising flight, the wingbeat slows to about 10-15 beats per second.
Flight initiation
What triggers a katydid to actually take flight? Some key stimuli include:
- Change in light intensity – Katydids often take off at dusk when light levels drop.
- High humidity – Moist conditions prevent dehydration during flight.
- Preferred temperature – Optimal flying temp is around 20-30°C for most species.
- Mate-seeking – Males fly toward female pheromones once detected.
- Food-seeking – Flying to reach new host plants.
- Predator avoidance – Fleeing from imminent danger such as a predator strike.
Katydids are exothermic, so external temperatures dictate their activity levels. When conditions align favorably, mature adults with fully developed wings may spontaneously take to the air. However, mating and foraging needs appear to be the main motivators for flight in most cases.
Lab experiments have shown that katydids housed together in crowded cages have a greater tendency to initiate flight when released. This supports the idea that dispersal instincts are triggered by overcrowding and competition for resources.
Hazards faced during flight
Despite their adaptations, flying katydids still face substantial hazards including:
- Predation – Bats and birds pick katydids out of the air.
- Exhaustion – Long flights drain fat reserves and cause exhaustion.
- Dehydration – Moisture loss is a risk especially on hot, dry nights.
- Disorientation – Landmarks help migrating katydids navigate over long distances.
- Storms – Gusty winds ground katydids and rainstorms can batter them.
Katydids lack wingspans wide enough to ride uplifting thermal air currents the way birds do. They must actively flap their wings continuously to stay aloft. The metabolic demands of prolonged flight without replenishing energy reserves can take a toll.
Choosing the right weather conditions reduces risks. Migrating katydids wait for favorable tailwinds that help maximize flight range. Cool, humid nights minimize overheating and moisture loss.
Studies show mortality rates during migratory journeys of 50% or higher. However, this high-risk dispersal strategy helps expand populations into new territory.
Flight speeds
The flight speed of katydids varies by their size and wing structure. Large species with broad wings typically fly faster than smaller ones with narrower wings. Here are some estimated flight speed ranges:
| Katydid species | Approx. flight speed |
|---|---|
| Great green bush cricket | 11-15 mph |
| Oblong-winged katydid | 7-11 mph |
| Conehead katydid | 5-9 mph |
| Shieldback katydid | 3-5 mph |
| Meadow katydid | 2-4 mph |
The fastest katydid fliers like the great green bush cricket can reach speeds comparable to perching birds, albeit for shorter durations. Slower katydids may hover in place or make brief gliding flights.
In still air, katydids typically fly close to the ground at heights under 3-6 feet. But during migrations they may reach altitudes up to 300 feet or more. The highest altitude documented for migrating katydids is over 750 feet.
Katydids orient themselves into the wind during takeoff to gain extra lift and elevation. Once airborne, they gradually correct their heading toward their destination using visual landmarks.
Conclusion
Katydids possess a remarkable ability among insects to engage in powered flight. With over 6,400 existing species, katydids occupy diverse ecological niches thanks in part to adaptations enabling flight. While routine katydid flights may cover only short distances, some migratory species travel surprising distances through feats of endurance.
The next time you hear the vibrant calls of katydids at night, take a moment to appreciate the hidden flight capabilities of these fascinating orthopterans. Their aerial journeys not only expand katydid populations but also connect far-flung habitats in nature’s grand scheme.
