Insects are kind of a big deal. As many as 30 million species make up this ecologically important class, only a fraction of which we know about. Around 80 percent of all animal species are insects. Estimates put their numbers in the quintillions.

Not that you'd easily know that if you opened a random introductory biology textbook - these are much more likely to give vertebrates a starring role. So it might be time to put the spineless members of the animal kingdom back into the spotlight.

A recent survey of 88 popular entry-level texts published between 1906 and 2016 found insects just weren't filling the pages in a way that reflected not just their abundance, but their significance in ecology.

"Insects are essential to every terrestrial ecosystem and play important roles in everything from agriculture to human health," says North Carolina State University biologist Jennifer Landin.

"But our analysis shows that students taking entry-level biology courses are learning virtually nothing about them."

Most surprisingly, this deficit has been on the increase since the 1960s. Our interest in the humble bug just isn't what it used to be. And that's a problem, according to the researchers.

"We do not exist apart from nature," Landin says.

"Humans and insects, for example, have direct effects on each other – and that is no longer clearly presented in the teaching literature."

To explore how generalised biology textbooks have changed over time with respect to their choice of content, the researchers combed their selection of textbooks for words, figures and illustrations that featured some kind of insect.

These were then recorded against the book's year of publication, revealing a gentle slide in the percentage of textbook pages dedicated to insect anatomy, lives, and relationships.

A century ago, you could expect an average of 32.6 pages to be devoted to something insecty. That's about 8.8 percent of the total.

Fast forward to books published between 2000 and 2016, that number drops to 5.67 pages. A miserable 0.59 percent.

As if that's not bad enough, the team found a huge imbalance in the categories of these super important arthropods.

Orthoptera – such as locusts and crickets – were overrepresented. They make up just 2 percent of insect species, but occupied as much as a quarter of the insect real estate.

Beetles, of the order Coleoptera, also represented about a quarter of those pages, in spite of making up a whopping 37 percent of all species of insect.

You could argue that big numbers don't necessarily make for an important group of animals. There's only so many pages in a textbook, and only so much time to study them all – finding the right representatives requires a little more nuance.

But in addition to a quantitative assessment, the team examined the kinds of words used to describe insects, and assigned them an emotive value as viewed by a relative entomological novice.

So while 'pest' might well be fairly denotative to an expert, to the average first-year student this would make an insect look less like the hero of the story.

Texts published prior to the 1960s contained 8.7 times more descriptors, of both a positive and negative variety, than those published after 2000.

However, those words tended to be a little more positive. We might not be as colourful in our descriptions today, but the occasional connotations appear to be less in the insect's favour.  

So not only are we talking about ants, moths, and flies less, we're less likely to be flattering in our descriptors.

"We saw societal shifts in the groups of insects addressed in texts; butterflies were covered more when butterfly collecting was a popular hobby, mosquitoes and other flies were overwhelming in books when insect-transmitted disease was rampant," says Landin.

This social relevance is to be expected in textbook trends. But far from becoming less important, a decline in insect numbers thanks to climate change is a concern we face in future decades.

We want our future biologists to be not just informed on 80 percent of all animal species, we want them to be excited by them.

It's time to back the bugs!

This research was published in American Entomologist.