Summer Holiday Fun with Bugs

Did you know that bugs have big summer holiday plans around Aotearoa? Summer is a busy time for invertebrate animals as they shake off the cold and soak up the sun (or soak up the warm weather while lounging in the shade, as some bugs do not like to be out in the sun).  

The candidates for the 2024 Bug of the Year contest provide some notable examples of what bugs get up to over our summer holidays. What do the Rangatira spider, hobbit psyllid, and praying mantis have in common at this time of year? How about the katipō and black cockroach-hunter wasp? We have included a few stories featuring the 2024 nominees here; to learn more about the contest and the bugs competing to be the winner, check out bugoftheyear.ento.org.nz/2024-bug-of-the-year-nominees/ 

Soaking up the Sunshine 

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If you are out on a sunny summer day, you will notice all sorts of bugs, especially butterflies, flying around. Ectotherms (another term for “cold-blooded animals”) rely on warm weather to get their blood pumping before they are ready to move around. On sunny days, you might see kahukura or pepe pouri staying still on a sunny spot with their wings open (Fig. 1A & D). This is called “basking.” When an ectotherm rests in a sunny spot, they are warming their body up – like they are recharging their solar batteries. Kahukura often bask on leaves and flowers in gardens or clearings, and pepe pouri often bask on the treetops of beech forests.   

 
Figure 1: There are two butterflies competing in this year’s Bug of the Year competition, the kahukura and the pepe pouri. (A-C) Kahukura, New Zealand red admiral butterfly shown basking (A), feeding (B), and feeding as a caterpillar (C);(D-F) Pepe pouri, forest ringlet butterfly shown basking (D), perching (E), and as a caterpillar (F). 

When butterflies feed on nectar or lay eggs, they do so with their wings folded(Fig. 1B & E). If you sneak up on a basking butterfly to get a photo, it will fold its wings. The underside of their wings is less colourful, which can provide camouflages so they are not as obvious to predators. Kahukura lay their eggs onto ongaonga | stinging tree nettle, where the larvae are protected from predators by the stinging hairs (Fig. 1C). Pepe pouri lays eggs on sedges or tussock, where the larva’s body colour matches the plant so it can hide from predators (Fig. 1F).   

Did you know that Tūhura Otago Museum has the largest collection of Lepidoptera (butterflies and moths) in the country? This collection and its record of where and when the insects were found can help researchers and conservation planners figure out where all the distinct species live and how that has changed over the years.  

Is there something you can do to help native butterflies? Yes! You could create pockets of suitable habitat in your garden by planting the butterflies’ preferred food or breeding plants, or support conserving the native forests where the butterflies are found. 

Dragonflies, such as the kapowai, cannot fold their wings like butterflies can. When they land, whether basking or feeding, their wings always lie flat (Fig. 2A). Why aren’t they more of a target for predators? Unlike butterflies, dragonfly wings are translucent (clear). Often, when they land on a piece of vegetation, they just look like a stick (Fig. 2B). If you are hungry for bugs, sticks are not going to look very appetising.  

 
Figure 2: The kapowai, Carové’sgiant dragonfly, is competing in this year’s Bug of the Year competition. When the adult dragonfly lands, the wings always lie flat (A). Because the wings are clear, this can make an adult dragonfly look like a stick (B). The dragonfly nymphs (juveniles) live in freshwater streams and lakes (C).  

If you are near a lake this summer, you might notice dragonflies dipping their abdomens in the water. This is where they lay their eggs. Dragonfly nymphs are aquatic and predate upon other bugs in the water. When they are fully grown, they will crawl up a stem or a tree near their water source, then shed their “exuviae” (the term for their moult) and emerge as an adult dragonfly. Just as butterfly larvae do not look much like the adults they develop into, dragonfly nymphs do not look much like dragonfly adults (Fig. 2C). 

Hanging Out at the Beach 

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When you are at the lake or beach this summer, how many different bugs can you find? Maybe you notice some dragonflies skimming the surfaces of lakes (which themselves are going to be teeming with aquatic invertebrates), but you won’t find too many insects or spiders in the ocean water. Instead, you will find terrestrial invertebrates spending time together in the sand or around the vegetation in the sand. 

Katipō are exclusively found in sand dunes, typically feeding on crawling insects that stray into their webs (Fig. 3). The spiderlings hatch from egg sacs in January and February and often use a “ballooning method” to disperse into surrounding plants. This is where the young spiders use air currents to carry themselves away from the nest while suspended by a single web strand. 

 
Figure 3: Female katipō (large black and red spider, top) with an egg sac and a male katipō (small brown and white spider, bottom) close by. 

Ngaro wīwī | black cockroach-hunter wasp build their nests in shingle and sand on the banks of streams or coastal beaches (Fig. 4A). As their name implies, these adult wasps (which are about the size of a fruit fly) hunt for cockroaches to bring back to their nest to feed their developing larvae (Fig. 4B). Ngaro wīwī construct nests in the sand (Fig. 4C); their young remain deep in a burrow waiting for snacks brought back by the adult. Hunter wasps are considered solitary, though multiple adults might construct their nest in the same area (referred to as a community). 

 

Figure 4: The ngarowīwī, black cockroach-hunter wasp is a nominee for Bug of the Year 2024 (A). As its name implies, adults hunt for cockroaches to feed their young (B). An adult wasp emerges from the entrance to her nest in a sand dune (C).  

Helping in the Garden 

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When you think about a garden, you are imagining the beautiful flowers, crops, and other plants in a yard. But there are so many things above and below the soil that we might forget to consider. For example, the globular springtail (Fig. 5A) might be living in the soil, aiding with nutrient cycling and helping to form soil microstructure. Meanwhile, adult orange-spotted ladybird beetles (Fig. 5B) can happily munch 100 aphids in one day (larvae can eat their own bodyweight’s worth!). Soil nutrition and pest removal are two important aspects of keeping a splendid summer garden.  

Climbing Trees 

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Finding the perfect tree to climb in the summer comes with so many rewards. The Rangatira spider (Fig. 6A) climbs trees on the offshore islands of Rēkohu | Wharekauri | Chatham Islands, hunting for prey (they love eating wētā!). The hobbit psyllid (scientific name Psylla frodobagginsi, named after Frodo Baggins from the Lord of the Rings trilogy) lives exclusively on kōwhai trees (Fig. 6B). And the New Zealand praying mantis can be seen gathering on the branches of small mānuka and kānuka trees (Fig. 6C).  

Feasts After Dark, in the Dark 

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Even after the sun goes down, nighttime in summer can still be warm enough to hang out with friends. Many of our Bug of the Year 2024 nominees prefer to wait until it’s dark before they join the party. The hura (Fig. 7A), superb giant land snail (Fig. 7B), Mt Arthur giant wētā (Fig. 7C), and ngāokeoke (Fig. 7D) all wait until dark before they emerge from their sleeping nooks to hunt. Because they hunt at night and do not have well-developed eyes, they rely on odours and vibrations to help them locate and capture their prey. The Mt Cook flea (Fig. 7E) is a type of wētā and mostly nocturnal too, but it is often seen in the middle of the day, making it particularly unusual among cave wētā. 

 

Figure 7: Many invertebrates prefer to emerge at night to feed or live in places where it is usually dark. The hura(A), superb giant land snail (B), Mt Arthur giant wētā (C), ngāokeoke(D), and Mt Cook flea (E) remain hidden during the day and emerge at night to find food. Titiwailive in caves and produce bioluminescence to attract prey (F). All are nominees for the 2024 Bug of the Year competition. 

Titiwai (Fig. 7F) might be considered nocturnal as well because they spend most of their lives in dark caves and grottos, so they can be active any time of day as long as it is dark. As carnivorous larvae, titiwai lure other insects with a long silken snare laden with sticky droplets. When an insect gets trapped, the titiwai reels in the snare and devours the prey and snare all at once. Titiwai emerge as adult fungus gnats during the winter (Fig. 8), and they only live about 3–4 days in order to mate and lay eggs on a suitable wall. Summertime, therefore, is all about the kids glowing and feasting in the caves.  

 

Figure 8: Titiwai adults live only about 3–4 days in winter. Arachnocampa luminosa Skuse 1890, collected April 1889, Wilton Botanical Garden, New Zealand.  

Listening to Summer Tunes 

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Aah, the sounds of summer. Some of the greatest hits found in the bug world are sung by chirping cicadas by day and stridulating grasshoppers in the evenings. Some days it seems like there are more cicadas and grasshoppers chirping than birds in the sky! But did you know that among our musical Bug of the Year 2024 nominees, the minute grasshopper is listed as “Threatened – Nationally Vulnerable” (Fig. 9A), and the scree cicada is listed as “At Risk – Naturally Uncommon” (Fig. 9B)? In other words, when you hear the chirping and stridulating sounds of summer, it is not likely that those sounds are coming from our nominees. 

Figure 9: The minute grasshopper (A) and scree cicada (B), both competing in this year’s Bug of the Year competition, are listed as “Threatened – Nationally Vulnerable” and “At Risk – Naturally Uncommon” (respectively) by the New Zealand Threat Classification System (NZTCS). 

Gathering in Numbers 

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Insects and spiders are everywhere, sometimes gathering in vast numbers, so it might seem inconceivable that some species are at risk of extinction. This year, 11 of the 20 nominees for New Zealand Bug of the Year are considered Threatened or At Risk. 

Invertebrates, like their vertebrate cousins, receive some level of attention and protection in Aotearoa | New Zealand. In fact, the Cromwell chafer beetle (Fig. 10A) is the only beetle in the world with its own reserve! Cromwell chafers are nationally endangered and can only live on inland sand dune ecosystems. The larvae live underground, feeding on the roots of plants. The adults spend their time underground too, but on summer nights when the conditions are right, the adults emerge, and the reserve comes alive with a carpet of crawling beetles. The adults roam around, feeding on lichens and other foliage. But these beetles are not just fussy about where they live; if the wind suddenly changes or the temperature drops, the beetles will pop right back underground in a matter of seconds! 

The tuatara tick (Fig. 10B) is another insect considered At Risk, as it is only found on four of the 12 island groups where tuatara reside. These ticks feed exclusively on tuatara blood and are often lost or deliberately removed when tuatara are translocated. The tuatara tick does not cause significant harm to its host; tuatara that have high tick loads (as many as 500 ticks have been counted on a single tuatara!) may experience small reductions in body condition over time, but otherwise the ticks appear to coexist with their host well.  

Figure 10: Eleven of the 20 nominees for New Zealand Bug of the Year are listed as Threatened or At Risk by the New Zealand Threat Classification System (NZTCS). This includes the Cromwell chafer beetle (A) and the tuatara tick (B).