The efficacy depends on various factors, like specificity of the predator, availability of other prey species, spatial and daily activity pattern of the prey and predator etc.

The encounter is an important aspect in efficacy. I think the correlation analysis of predator density to prey density over a considerable period, with due consideration of lifespan of prey and predator will be the easiest method to evaluate efficacy.

Yes, to complement the answer by Rubin Philip, I am giving my comments.

For assessing the efficacy of predators like ladybird beetles, we need to consider two aspects related to density responsiveness viz., functional and numerical responses by the predator species. The predators should be offered prey in different densities from low to high and fitting regression equations to find out the relationship between prey density and feeding efficiency (functional response), and prey density and predator fecundity/ or progeny produced numerical response). Additionally, predator exclusion i.e comparing pest populations in experimental plots with and without predators introduction will give better picture on predator efficacy.

lady bird beetles are very much effective predators of enemies insects especially aphids. The nature has its own settlements as prey increases the predators gradually breeds more and hence prevails in abundance and vice versae , so a natural eco- balance is maintains towards economic threshold level purely a natural and sustainable natural Eco-system upon which we confidently rely on.

There are many experiments you can do to evaluate a predator especially ladybirds. From very simple ones in Petri dishes or caged plants (probably better) placing their prey and look at how much they consume to more complicated studies in the field, looking at their effects as predators in combination with other predators or parasitoids, multitrophic interactions, intraguild predation studies. But I would start with a simple lab study plant+prey+ coccinellids( good to test larvae and adults)

Dear Aadarsh, Send me an email at [email protected] and tell me which species of coccinellid you are working on and whether they are aphidophagous (aphid eaters or not) and I can let you know more and find you some simple papers that you can follow for your experiments. The gentlemen that replied to you suggesting functional and numerical responses are offering very good suggestions too. Best wishes K

Dear research fellow,

Your question is very practical indeed. And all answers provided to you above have a sound contribution. Babasaheb Fand gave you an important input and others completed well. When ever you study natural enemies efficiency as predators on pests, you need to have some basic ecological knowledge on both the predator and the preys. For instance first, their life cycle history so you can use all stage element in your evaluation with all instar larvae, pupae to adult. So as i did that with Oecophylla smaragdina on bagworm defoliators, you may see some eventual preferences for prey (time of the first attack for which prey i.e all life cycle individuals tested at laboratory). Get your index of preference from 0 to 1. Some literature review on this will help you more (life cycle history). And preferably be more specific on your insect target group and make sure that you are assessing the right one. The ladybugs is not a generalist predator, but rather attack specific insects (bugs). That will make your life more simple in the beginning. I suggest to you to use video recording on 24 hours basis with both focal and scanning sampling testing in lab.

You can even make a good research by comparing both abiotic (air temperature, relative humidity) to establish any correlation and predictive effects from them and biotic factors. That can become a strong paper. You can get mini weather station that consider microclimate conditions within your lab or field. If you have the statistical sofware Sigma plot 11 or 12, you can obtain good graphs calculating for you directly the correlation with Pearson Moment or others. As suggested to you early; regression equation will show you which parameters is responsible for your predator behaviors eventually. Try to follow this practical lead:

1. You need to make some general observation after identifying the right insect pest prey on the crops if possible with an exposure with those ladybugs. Follow a systematic observation by naked eyes from early morning, midday, afternoon, evening and night time. This will provide you with valuable information. That would be more of a scanning sampling.

2. From that first part, you need to conduct a more intensive laboratory predatory behaviors evaluation as advised to you above by various friends. Use video recording with any digital camera (tripod) having the software that enable you to make photos of those videos by seconds sequences; so you can have 24 hours focal observations. Using naked eyes still but once you are tired, you can support with that or do it with your team. By any means those records will lend you in more details of valuable data.

3. If possible having the mini weather station set will provide more data to establish your correlation and regression equations.

4. Eventual index of preference towards various instar larvae, pupae or adult stage insects?

I wish you all the best...from Pierre (France Martinique Island near Miami Florida).

The efficacy of Ladybugs as predators can be evaluated with the reproductive potential specially pre-consumption rate, fecundity, longivity, searching ability and adaptability to environment.

Yes Tukaram Sathe is adding another important component. In fact the efficacy of any biological agent depends a lot on the stability of the population dynamic in the long term to enable a relative satisfactory pest control. Fecundity and survival rate will be two main factors of this stability...Once you have cleared the steps from your lab experiments and establish this efficiency, eventually you can proceed to a mass release of ladybugs in an outbreak infested crop.